JP6528302B2 - Seal structure of linear motion system, piston member - Google Patents

Description

  The present invention relates to a piston member that receives an external force, a fluid sealing structure in a linear motion rod that holds the piston member, and the like in a linear motion system.

  There are many linear motion systems, such as hydraulic cylinders, Bingham dampers, air cylinders, shock absorbers, etc., that create a reciprocating motion according to the purpose. These linear motion systems often include a piston member that receives fluid pressure and a linear motion rod that holds the piston member, and controls the reciprocating motion using the piston member, and the reciprocating motion is It is configured to output or reduce power through the rod.

  For example, in a hydraulic cylinder or the like, a piston member and a linear motion rod are disposed in a tubular tube. Hydraulic pressure is supplied into the tube to cause the piston member to reciprocate as desired to extract motion from the linear motion rod.

  In order to fix the piston member and the linear motion rod, a screw is generally used. Specifically, a male screw is formed in the vicinity of the end of the linear motion rod, and in a state where the piston member is fitted, the female screw is screwed to the male screw to fix the piston member so as to sandwich it. It has a structure.

  When fastening the female screw body, inserting a washer or a cushion sleeve around the linear motion rod is performed. These members protect the piston member from buckling, flaws and the like at the time of fastening, and conversely, suppress the loosening of the screw body by positively pressing the piston member.

  In addition, a piston ring (outer seal member) is provided on the outer peripheral surface of the piston member in order to enhance the sealing property of the working fluid in the tube. The outer seal member is generally made of a synthetic resin material, and is forcibly fitted to the fitting groove extending in the circumferential direction on the outer peripheral surface of the piston member while elastically deforming the outer seal member to the expansion side Match.

  Similarly, an inner seal member is also provided between the linear motion rod and the piston member. The inner seal member is also generally made of a synthetic resin material, and is fitted to the fitting groove extending in the circumferential direction on the inner peripheral surface of the piston member while elastically deforming the inner seal member to the contraction side Let

  Japan Industrial Standard JIS B 8368 hydraulic cylinder

  In the case of a structure in which the seal member is fitted while being elastically deformed with respect to the groove of the piston member, the synthetic resin of the seal member must be one having high stretchability, and there is a problem that the freedom of material selection is narrow. there were. Therefore, the friction resistance is high, and deterioration with respect to the working fluid is unlikely to occur. However, even if the material is present, it may not be used for the seal member.

  In addition, when the seal member is elastically deformed in order to fit the piston member, there is a problem that the seal member is cracked or broken. On the other hand, in order to reduce the amount of elastic deformation of the seal member at the time of installation, the fitting groove of the piston member must be made shallow, and there is a problem that the axial engagement between the piston member and the seal member becomes weak. .

  Further, since the external force of the working fluid is repeatedly applied to the piston member, the female screw is gradually loosened, and the fastening between the piston member and the direct acting rod is released. In order to prevent loosening of the female screw body, the female screw body is strongly tightened, but this is not an essential solution and there has been a problem that the piston member and the linear motion rod are prone to fatigue failure. .

  In order to prevent the female screw body from loosening, for example, a snap ring may be fitted to the outer side of the female screw body. If a snap ring is used, it is possible to prevent the female screw body from coming off from the shaft, but there is a problem that the female screw body can not be prevented from loosening. In addition, since the snap ring has a relatively thin or thin wire diameter, the snap ring is easily broken and has difficulty in strength.

  In addition, in the case of forming a step on the linear motion rod, allowing the piston member to abut on the step, and sandwiching and fixing with a female screw, it is necessary to make the diameter of the linear motion rod smaller stepwise toward the shaft end is there. As a result, although the diameter of the external thread formed at the end of the linear motion rod is the smallest, it must be able to receive all the forces acting on the piston member. As a result, it becomes difficult to increase the cross-sectional area (diameter) of the male screw alone, and in order to provide the step, the body side of the linear motion rod must be designed thicker than necessary. There is a problem that the accompanying increase in weight, increase in the amount of processing, and the like increase the cost.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems and has been achieved through intensive studies by the inventor of the present invention, and provides a seal structure and the like in a linear motion system that is easy to assemble and can improve seal performance. With the goal.

  The present invention for achieving the above object comprises a piston body axially movably accommodated in a tube, and the linear motion rod holding the piston body and interlocking with the reciprocating movement of the piston body. A fluid seal structure applied to a linear motion system, comprising at least a part of the piston body, an insertion hole into which the linear motion rod is inserted, and an outer circumferential surface opposite to the inner circumferential surface of the tube A piston member having a seal portion for restricting the movement of the fluid in proximity to the inner peripheral surface, and the outer peripheral surface of the piston member, which is smaller in diameter than the seal portion and in the axial direction An annular outer seal fitting portion continuing to any one of a pair of end faces opposed to each other, an annular outer seal member abutting on the outer seal fitting portion of the piston member, and the piston member Is arranged near the end face, characterized in that it comprises an outer seal holding member for pressing axially said outer seal member to the outer seal fitting portion, a sealing structure of the linear motion system. The outer seal fitting portion can be configured to form an annular step portion having a bottom portion set to a smaller diameter than the seal portion.

  In relation to the seal structure, the outer seal holding member is fixed to an end face of the piston member.

  In relation to the seal structure, the outer seal holding member is characterized by having a holding member female screw portion screwed to the male screw portion of the linear motion rod.

  In relation to the seal structure, the male screw portion of the linear motion rod is formed with a first male screw spiral groove and a second male screw spiral groove having different lead angles and / or lead directions, and the piston member of the piston member The basic hole is formed with an internal thread portion for a piston screwed with the first external thread spiral groove of the linear motion rod, and the internal thread portion for the holding portion of the outer seal holding member is a screw with the second external thread spiral groove. It is characterized by matching.

  In relation to the seal structure, the peripheral surface of the outer seal fitting portion is characterized in a tapered shape in which the seal portion side has a large diameter and the end surface side has a small diameter.

  In relation to the seal structure, a pressing surface for pressing the outer seal member in the outer seal holding member is characterized by being formed in an annular tapered shape having a smaller diameter in the pressing direction.

  In relation to the seal structure, the linear motion rod and an annular inner seal member disposed between the piston member or the outer seal holding member, the piston member or the outer seal holding member It has an annular inner seal receiving hole which is continuous with one of a basic hole into which a moving rod is inserted and one of a pair of end faces opposed in the axial direction of the inserted member which is larger in diameter than the basic hole. The inner seal member is in contact with the inner seal receiving hole.

  In relation to the seal structure, a step or a tapered surface axially engaged with the inner seal member is formed on an outer peripheral surface of the linear motion rod.

  In relation to the seal structure, the peripheral surface of the inner seal accommodation hole is a tapered structure in which the basic hole side has a small diameter and the end surface side has a large diameter.

  In relation to the seal structure, in the shaft portion having the male screw portion, the linear motion rod is formed with a rod side cooperation region which is non-circular in cross section when viewed from the axial direction, and the piston member is inserted In the hole, a female screw portion screwed with the male screw portion and a piston side cooperation region which is not circular in cross section when viewed from the axial direction are formed, and the rod side cooperation region and the piston side cooperation region are external forces It is characterized in that it is structured to engage with each other in the circumferential direction while allowing relative rotation due to.

  In relation to the seal structure, the linear motion rod includes a linkage member having at least a part of the piston body and having an insertion hole into which the linear motion rod is inserted, wherein the linear motion rod is a shaft portion having an external thread portion The rod side cooperation area | region which will be seen from an axial direction and which becomes a cross-sectional non-regular circle is formed, The inner periphery becomes non-regular circle in one said insertion hole of the said piston member and the said cooperation member A piston side cooperation area engaged circumferentially with the cooperation area is formed, and in the other insertion hole of the piston member and the cooperation member, a piston female screw part screwed with the male screw part of the linear motion rod A relative rotation preventing mechanism is disposed between the piston member and the cooperation member, and the two members are engaged in the circumferential direction.

  In relation to the above-mentioned seal structure, it is characterized in that the above-mentioned cooperation member serves as the above-mentioned outside seal holding member.

  In relation to the seal structure, the basic hole of the piston member is formed with an internal thread portion to be engaged with an external thread portion of the linear motion rod.

  The present invention for achieving the above object comprises a piston body axially movably accommodated in a tube, and the linear motion rod holding the piston body and interlocking with the reciprocating movement of the piston body. A fluid seal structure applied to a linear motion system, the inserted member having at least a part of the piston body and having an insertion hole into which the linear motion rod is inserted, the linear motion rod, and the subject And an annular inner seal member disposed between the insert members, wherein the insert hole of the insert member has a diameter larger than the diameter of the basic hole into which the linear motion rod is inserted and the basic hole. And an annular inner seal receiving hole continuing to any one of a pair of axially opposed end faces of the inserted member, wherein the inner seal member is in contact with the inner seal receiving hole. Characterized by A seal structure of the linear motion system.

  In relation to the seal structure, a step or a tapered surface axially engaged with the inner seal member is formed on an outer peripheral surface of the linear motion rod.

  In relation to the seal structure, the peripheral surface of the inner seal accommodation hole is a tapered structure in which the basic hole side has a small diameter and the end surface side has a large diameter.

  In relation to the seal structure, the inserted member is a piston member having a seal portion which restricts the movement of the fluid in proximity to the inner peripheral surface on the outer peripheral surface opposed to the inner peripheral surface of the tube. The piston member has an annular outer seal fitting portion formed on the outer peripheral surface, having a smaller diameter than the seal portion, and being continuous to any one of a pair of end surfaces opposed in the axial direction. And an annular outer seal member that is in contact with the outer seal fitting portion of the piston member, and is disposed in the vicinity of an end face of the piston member, the outer seal member being on the outer seal fitting portion side And an outer seal holding member for pressing in the axial direction.

  In relation to the seal structure, the outer seal holding member is fixed to an end face of the piston member.

  In relation to the seal structure, the outer seal holding member is characterized by having a holding member female screw portion screwed to the male screw portion of the linear motion rod.

  In relation to the seal structure, the male screw portion of the linear motion rod is formed with a first male screw spiral groove and a second male screw spiral groove having different lead angles and / or lead directions, and the piston member of the piston member The basic hole is formed with an internal thread portion for a piston screwed with the first external thread spiral groove of the linear motion rod, and the internal thread portion for the holding portion of the outer seal holding member is a screw with the second external thread spiral groove. It is characterized by matching.

  A second inserted member having at least a part of the piston body and having an insertion hole into which the linear motion rod is inserted is provided in relation to the seal structure, and the male screw portion of the linear motion rod includes: A first male screw spiral groove and a second male screw spiral groove having different lead angles and / or lead directions are formed, and the first male screw spiral groove and screw of the linear motion rod are formed in the basic hole of the inserted member. A mating female screw portion is formed, and a female screw portion screwed with the second male screw spiral groove of the linear motion rod is formed in the insertion hole of the second inserted member.

  In relation to the seal structure, a circumferential surface of the outer seal fitting portion has a tapered structure in which the seal portion side has a large diameter and the end surface side has a small diameter.

  In relation to the seal structure, in the shaft portion having the male screw portion, the linear movement rod is formed with a rod side cooperation region which is non-circular in cross section when viewed from the axial direction, and the insertion member is In the insertion hole, a female screw portion screwed with the male screw portion and a piston side cooperation region which is non-circular in cross section when viewed from the axial direction are formed, and the rod side cooperation region and the piston side cooperation region are It is characterized in that it is structured to be engaged with each other in the circumferential direction while permitting relative rotation due to an external force.

  In relation to the seal structure, it comprises a second inserted member which constitutes at least a part of the piston body and has an insertion hole into which the linear motion rod is inserted, and the linear motion rod has a shaft having an external thread. The rod-side cooperation area is formed to have a non-circular cross section when viewed from the axial direction in the part, and the inner periphery of the insertion member in one of the insertion member and the second insertion member is non-circular. As a result, a piston-side cooperation region engaged circumferentially with the rod-side cooperation region is formed, and the other of the insertion holes of the inserted member and the second inserted member is formed of the linear motion rod. A female screw portion screwed with the male screw portion is formed, and a relative rotation preventing mechanism is disposed between the inserted member and the second inserted member, in which both are engaged in the circumferential direction.

  In relation to the seal structure, the basic hole of the inserted member is characterized in that a female screw portion screwed with the male screw portion of the linear motion rod is formed.

  According to the present invention for achieving the above object, a piston is accommodated in a tube so as to be axially movable and fixed to a linear motion rod in the tube to receive fluid pressure and transmit it to the linear motion rod A member formed on at least one of a pair of end surfaces facing in the axial direction and facing a pressure receiving surface for receiving the pressure of the fluid, an insertion hole into which the linear motion rod is inserted, and an inner circumferential surface of the tube A seal portion which is formed on the outer peripheral surface, and which is formed on the outer peripheral surface, the seal portion which restricts the movement of the fluid in proximity to the inner peripheral surface, and which is smaller in diameter than the seal portion and continues to the end surface A piston member having an annular outer seal fitting portion, wherein an annular outer seal member is configured to be locatable in the outer seal fitting portion.

  In relation to the piston member, a circumferential surface of the outer seal fitting portion has a tapered structure in which the seal portion side has a large diameter and the end surface side has a small diameter. That is, the annular bottom surface portion of the outer seal fitting portion is characterized by being tapered.

  In relation to the piston member, the insertion hole has a basic hole into which the linear motion rod is inserted, and an annular inner seal receiving hole having a diameter larger than the basic hole and continuing to the end face. An annular inner seal member can be arranged in the inner seal receiving hole.

  In relation to the piston member, the peripheral surface of the inner seal receiving hole is characterized by a tapered structure in which the basic hole side has a smaller diameter and the end surface side has a larger diameter.

  In relation to the above-mentioned piston member, the above-mentioned insertion hole is characterized in that a female screw part screwed with a male screw part of the above-mentioned direct-acting rod is formed.

  According to the present invention, in a seal structure or the like in a linear motion system, assembly is easy, and seal performance can be enhanced.

It is a figure which shows the assembled state of the seal structure which concerns on 1st embodiment of this invention. It is a front view of (A) direct-acting rod of seal structure concerning a first embodiment of the present invention, and a bottom view of (B) direct-acting rod. It is a front sectional view of (A) washer of seal structure concerning a first embodiment of the present invention, (B) Bottom view of a washer, (C) Top view of a piston member, (D) It is a front view of a piston member. It is a figure which shows the state in the middle of the assembly of the seal structure which concerns on 1st embodiment of this invention. (A) is a fastening state diagram of the piston member of a pi seal structure concerning a first embodiment of the present invention, and a washer, (B) thru / or (D) is a figure showing the modification. (A) thru | or (C) are the fastening state figures of the piston member and washer of the seal structure which concern on the modification of 1st embodiment of this invention. (A) thru | or (D) are the front view and bottom view of the direct-acting rod of the seal structure which concerns on the modification of 1st embodiment of this invention. It is a figure which shows the assembled state of the seal structure which concerns on the modification of 1st embodiment of this invention. It is an assembly state figure of the seal structure concerning a second embodiment of the present invention. It is a front view and bottom view of (A) direct-acting rod used for seal structure concerning a second embodiment of the present invention, and a bottom view of (B) washer. It is a side view and a bottom view of (A) direct-acting rod used for a seal structure concerning a modification of a second embodiment of the present invention, and a bottom view of a (B) washer. (A) (B) is an exploded view of the seal structure concerning the modification of a second embodiment of the present invention. (A) Assembly state figure of the seal structure concerning the modification of a first embodiment of the present invention, (B) It is an exploded view. (A) Assembly state figure of the seal structure concerning the modification of a second embodiment of the present invention, (B) It is an exploded view. (A) Assembly state figure of the seal structure concerning the modification of a second embodiment of the present invention, (B) It is an exploded view. (A) Assembly state figure of the seal structure concerning the modification of a second embodiment of the present invention, (B) It is an exploded view. It is a fragmentary sectional view showing the seal structure concerning a third embodiment of the present invention. It is the (A) sectional view showing the female screw object used with the seal structure concerning a third embodiment of the present invention, the (B) front view, and the (C) bottom view. (A) and (B) are the front view and bottom view which show the modification of the direct-acting rod used with the seal structure which concerns on embodiment of this invention. (A) And (B) is a fragmentary sectional view showing the modification of the seal structure concerning the embodiment of the present invention. It is a fragmentary sectional view showing the modification of the seal structure concerning the embodiment of the present invention. (A) And (B) is a fragmentary sectional view showing the modification of the seal structure concerning the embodiment of the present invention. (A) It is a top view of the seal structure which concerns on 4th embodiment of this invention. (B) It is a front view of an assembly structure. It is the sectional view on the AA line of Fig.23 (a). It is the figure which expanded and showed the external thread part of the linear motion rod. (A)-(d) It is the figure which showed the relative action | operation of a piston member and the internal thread for fixation. It is a front fragmentary sectional view which shows a relative rotation prevention mechanism. It is a front fragmentary sectional view and a bottom view of a male screw body for engagement used with a relative rotation prevention mechanism. It is the top view and front fragmentary sectional view of a washer used with a relative rotation prevention mechanism. (A) is a conceptual diagram which shows the effect | action of the saw blade of a relative rotation prevention mechanism, (B)-(D) is a conceptual diagram which shows the modification of a saw blade. (A)-(C) are conceptual diagrams which show the modification of the saw blade of a relative rotation prevention mechanism. (A) and (B) are the top view and front fragmentary sectional view of the washer used by the application example of a relative rotation prevention mechanism. They are the top view and front fragmentary sectional view which show the relative rotation prevention mechanism of the seal structure which concerns on 5th embodiment. (A) is a plan view and a front partial cross-sectional view of a washer used in the relative rotation prevention mechanism, and (B) is a front partial cross-sectional view showing an opening operation of the relative rotation prevention mechanism. (A) is a front fragmentary sectional view showing the opening operation of the washer used in the application example of the relative rotation prevention mechanism, (B) is a plan view showing the opening operation of the washer used in the application example and a front partial cross section FIG. (A) A plan view and a front partial cross-sectional view of a relative rotation preventing mechanism of a seal structure according to a sixth embodiment; (B) A front partial cross-sectional view showing a state in which a washer and an external thread for engagement are integrated; C) is a front fragmentary sectional view which shows a fastening state. (A) thru | or (C) is a top view which shows the application example of the same relative rotation prevention mechanism, (D) is the top view and front fragmentary sectional view of the washer used by another application. They are a top view and a front fragmentary sectional view of (A) washer, and a front fragmentary sectional view showing a fastening state of a relative rotation prevention mechanism of a seal structure concerning a 7th embodiment. They are the (A) top view concerning the application example of the seal structure, and the front sectional view (B). It is front sectional drawing which shows the cancellation | release state of the (A) fastening state of the seal structure which concerns on 8th embodiment, and the (B) relative rotation prevention mechanism. It is front sectional drawing of the seal structure used as the application example of 4th to 8th embodiment. It is front sectional drawing of the seal structure which is another application example of 4th to 8th embodiment. It is front sectional drawing which expands and shows the external thread part of the linear_motion | direct_drive rod of the seal structure used as the other application of 4th to 8th embodiment. It is front sectional drawing of the seal structure which is another application example of 4th to 8th embodiment. It is front sectional drawing of the seal structure of 9th embodiment. It is front sectional drawing which shows the application example of the seal structure of 9th embodiment. It is a sectional view showing the basic composition of the hydraulic piston concerning the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. First, the basic structure of a hydraulic piston as an example of a linear motion system to which the seal structure 1 of the present invention can be applied will be described with reference to FIG. The hydraulic piston includes a piston body 300 functioning as a piston, a direct acting rod 10 functioning as a piston rod, a tube 4, a rod cover 5, and a head cover 6. The piston body 300 is configured of, for example, a plurality of members, is fixed to the linear motion rod 10, and is disposed in the cylindrical tube 4. In the tube 4, a ring-shaped rod cover 5 is disposed on the side from which the linear motion rod 10 protrudes, and the head cover 6 is disposed on the opposite side. Therefore, a pressure space is formed inside by the tube 4 being covered by the rod cover 5 and the head cover 6 at both ends. Further, in the vicinity of both ends of the tube 4, openings 7, 8 for taking in and out the working fluid in the tube 4 are formed, and oil is allowed to flow into the pressure space through the openings 7, 8 and the piston body 300 is moved. It has a structure that

  FIG. 1 shows the seal structure of the linear motion system according to the first embodiment. The seal structure is configured to include the linear motion rod 10, an annular washer 50 as a cooperating member, and the piston member 100. A piston ring (outer seal member) 90 is provided around the piston member 100. The piston 50 is configured by the washer 50, the piston member 100, the piston ring 90, and the like. Here, various members into which the linear motion rod 10 is inserted are also expressed as “inserted members”, and these constitute a part of the piston body 300. Therefore, the washer 50 and the piston member 100 become an inserted member.

  The piston member 100 is a cylindrical member, and has an annular outer peripheral surface 105 opposed to the inner peripheral surface of the tube 4, a pair of end surfaces 101 opposed in the axial direction, and an insertion formed coaxially with the outer peripheral surface. It has a hole 100a. The outer circumferential surface 105 is close to the inner circumferential surface of the tube 4 to form a seal portion 105 a that restricts the movement of the working fluid. At least one of the end surfaces 101 is a pressure receiving surface 101a that receives the pressure of the working fluid. The linear motion rod 10 is inserted into the insertion hole 100a.

  Further, on the outer peripheral surface 105 of the piston member 100, an annular outer seal fitting portion 210 which is continuous from the middle to the end surface 101 on the washer 50 side is formed. The outer seal fitting portion 210 constitutes a small diameter surface 201 which is continuous to the end surface 101 on the washer 50 side on the circumferential surface, and the piston ring 90 is inserted therein, abutted and fitted. The small diameter surface 201 is smaller in diameter than the outer peripheral surface (seal portion 105 a) of the piston member 100, and the piston ring 90 is positioned in the axial direction by the seal portion 105 a and the step 205 formed on the small diameter surface 201. The axial dimension of the piston ring 90 is set to be slightly larger than the axial dimension of the small diameter surface 201, and the piston ring 90 minutely protrudes from the piston member 100 toward the washer 50. The washer 50 is set larger in diameter than the small diameter surface 201. Therefore, when the washer 50 and the piston member 100 are fastened, the end face of the washer 50 abuts on the piston ring 90 and the piston ring 90 is fixed. That is, the piston ring 90 is held between the piston member 100 and the washer 50. The washer 50 is disposed in the vicinity of the end face of the piston member 100 and functions as an outer seal holding member for pressing the piston ring 90 toward the outer seal fitting portion 210 side.

  As a result of the above, the piston ring 90 can be easily assembled as compared with the conventional case where the sealing member is elastically deformed and fitted and installed. Along with that, since it is not necessary to consider elastic deformation of the piston ring 90, it is possible to freely select a material of high rigidity and high wear resistance.

  As shown in FIG. 2A, the linear motion rod 10 has a main body 12 a and an end 12 c in the shaft 12. A step 20 is formed at the boundary between the main body 12a and the end 12c, and a rod side seat 22 is formed at a portion corresponding to a lower portion or a root of the step 20. The main body 12a has a cylindrical shape. An external thread 13 is formed at the end 12 c.

  As shown in FIG. 2 (B), at the end 12c, a rod-side cooperation area 17 which is non-circular in cross section as viewed in the axial direction is formed. Here, the rod-side cooperation area 17 is formed on the proximal side of the male screw 13 at the end 12 c. Specifically, the rod side cooperation area 17 has a shape in which a partial arc of the cross section of a regular circle is omitted (deformed) along the chord, and the part of the chord corresponds to the rod side contact portion 23 Become. As a result, on the circumferential surface of the end portion 12c, the rod-side contact portion 23 is a plane perpendicular to the radial direction and directed radially outward. The rod-side contact portion 23 has a distance from the axial center of the screw that varies along the circumferential direction, and the first rod-side contact region 23Y has a distance X1 along one circumferential direction X of the linear motion rod 10, X2 becomes large. In the second rod side contact region 23X, the distances Y1 and Y2 increase along the other circumferential direction Y of the linear motion rod 10. Note that this fluctuation amount is set to be the same as the washer-side contact portion 53 described later, if a slight extra clearance is ignored. Alternatively, the clearance may be set to be filled by the deformation in the direction perpendicular to the axis caused by the axial compression by the tightening of the washer 50 by the piston member 100.

  Further, the minimum radius 17Y from the axial center of the rod-side cooperation area 17 is set equal to or greater than the maximum radius 13X from the axial center of the male screw portion 13. Therefore, it is preferable that the maximum radius 17Y from the axial center of the rod side cooperation area 17 be set larger than the maximum radius 13X from the axial center of the male screw portion 13.

  As shown in FIGS. 3A and 3B, the first receiving portion 60 is formed on the surface on one side of the washer 50. The first receiving portion 60 is opposed to the seat portion 102 of the piston member 100, and a first relative rotation preventing mechanism A is formed between the two. When the first relative rotation preventing mechanism A tries to rotate in a direction in which at least the piston member 100 is loosened with respect to the linear motion rod 10, the first receiving portion 60 and the seat portion 102 of the piston member 100 mutually Engaging to prevent relative rotation between the first receiving portion 60 and the rod side seat 22 in the rotational direction. A second receiving portion 70 is formed on the other side of the washer 50. The second receiving portion 70 faces the step portion 20 of the linear motion rod 10.

  The insertion hole 52 of the piston rod in the washer 50 is non-circular when viewed from the axial direction. The insertion hole 52 has a shape in which a partial circular arc of a regular circle is omitted along the chord, and circumferentially engages with the rod-side cooperation area 17 of the linear motion rod 10 (this washer The cross-sectional non-circular area in the 50 insertion holes 52 is defined as the "piston side cooperation area", and the engagement structure between the piston side cooperation area and the rod side cooperation area 17 is defined as the "auxiliary relative rotation prevention mechanism B") .

  Specifically, the auxiliary relative rotation preventing mechanism B includes a washer side contact portion 53 formed in the insertion hole 52 of the washer 50 and a rod side contact portion formed in the rod side cooperation area 17 of the linear motion rod 10. Have twenty three. As described above, the insertion hole 52 of the washer 50 has a partial arc shape concentric with the axial center of the screw, and the remaining portion is cut off like a chord into a straight line. The strings become the washer-side contact portions 53. Therefore, the inner wall of the insertion hole 52 of the washer 50 has a planar shape at a portion corresponding to the washer-side contact portion 53, and the distance from the axial center of the screw varies along the circumferential direction. Specifically, in the first washer side contact area 53X, the distances XA and XB increase along one circumferential direction X of the washer 50. In the second washer side contact area 53Y, the distances YA and YB increase along the other circumferential direction Y of the washer 50. In addition, the part except the washer side contact part 53 becomes a regular circle shape from which the distance from the axial center of a screw becomes fixed. Further, the minimum radius 52Y from the axial center of the insertion hole 52 is set to be equal to or larger than the maximum radius 13X of the male screw portion 13. As a result, the insertion hole 52 and the male screw portion 13 of the linear motion rod 10 do not have to interfere with each other.

  Therefore, when the end 12c of the linear motion rod 10 is inserted into the insertion hole 52 of the washer 50, the washer side abutment portion 53 and the rod side abutment portion 23 abut each other, and the axial center of the screw remains aligned The relative rotation of the two in the circumferential direction is restricted. That is, the washer side contact part 53 and the rod side contact part 23 function as the auxiliary relative rotation preventing mechanism B.

  Furthermore, as the first relative rotation preventing mechanism A, the first receiving portion side unevenness 64 that engages with the piston side unevenness 104 is formed in the first receiving portion 60 of the washer 50. The first receiving portion side unevenness 64 has a saw blade shape provided continuously in the circumferential direction. The direction in which each of the first receiving-side concavities 64 extends, that is, the direction in which the ridge line extends, is along the radial direction of the washer 50. As a result, the first receiving portion side unevenness 64 radially extends from the center of the through hole 52 of the washer 50.

  Further, the first receiving portion 60 is formed with a washer-side tapered surface which is inclined in the radial direction. Since this washer side taper surface inclines so that the center side may approach the step part 20 side of the direct-acting rod 10 (refer FIG. 1), it becomes a concave conical shape as a result. The first receiving portion side unevenness 64 described above is formed on the washer side tapered surface.

  As shown in FIGS. 3C and 3D, the insertion hole 100a of the piston member 100 is formed with a female screw portion 106a for screwing with the linear motion rod 10. Further, the piston member 100 is formed with a seat portion 102 opposed to the first receiving portion 60 of the washer 50. The seat portion 102 and the first receiving portion 60 on the side of the washer 50 both form an annular surface area, and abut on each other to transmit the fastening force (axial force) to the step portion 20. That is, most of the axial force in the present fastening structure is transmitted to the step 20 through the washer 50. Also, the piston ring 90 is held by the piston member 100 and the washer 50 by this axial force.

  As shown in FIG. 3, as the first relative rotation preventing mechanism A, a female screw side unevenness 104 is formed on the seat portion 102 of the piston member 100. The female screw-side unevenness 104 has a saw blade shape provided continuously in the circumferential direction. The direction in which each of the female screw-side irregularities 104 extends, that is, the direction in which the ridge line extends is the radial direction of the piston member 100. As a result, the female screw-side unevenness 104 radially extends from the axial center.

  Further, the seat portion 102 is formed with a radially inclined female screw side tapered surface. The female screw side tapered surface is inclined so that the center side approaches the washer 50 side, and as a result, it has a conical shape convex toward the step portion 20 side of the linear motion rod 10. The female screw-side unevenness 104 described above is formed on the female screw-side tapered surface.

  As described above, as the first relative rotation preventing mechanism A, the female screw side unevenness 104 and the first receiving portion side unevenness 64 have a plurality of sawtooth shapes continuous in the circumferential direction, so as a so-called ratchet mechanism or one-way clutch mechanism Works. As a result, at the time of fastening operation of the piston member 100, relative movement of the female screw side unevenness 104 and the first receiving portion side unevenness 64 of the washer 50 is allowed, and smooth relative rotation is realized. On the other hand, at the time of the loosening operation of the piston member 100, the relative movement of the female screw side unevenness 104 and the first receiving portion side unevenness 64 of the washer 50 is completely restricted. As a result, the workability at the time of fastening and the subsequent prevention of loosening can be rationally compatible.

  Furthermore, since the piston side taper surface and the washer side taper surface are formed in the seat portion 102 and the first receiving portion 60 as the first relative rotation preventing mechanism A, the contact area between the two can be increased. Further, the axial fastening force by the fastening structure also acts in the radial direction by the tapered surface. By pressing the tapered surfaces in the radial direction, centering can be performed in a self-excitation manner. As a result, the concentricity of the piston member 100 and the washer 50 can be enhanced, and the engagement accuracy of the female screw side unevenness 104 and the first receiving portion side unevenness 64 can be enhanced. In addition, it is also preferable to slightly increase the inclination of the convex surface-side tapered surface on the convex side and reduce the inclination angle of the concave surface on the washer-side surface to a minute difference so as to have a slight difference. In this case, the tapered surfaces can be brought into contact with each other little by little from the center toward the radially outer side as the tightening pressure increases.

  In addition, the auxiliary relative rotation preventing mechanism B prevents the shapes of the washer side contact portion 53 and the rod side contact portion 23 from becoming concentric circular with respect to the axial center of the screw. In other words, in the shapes of the washer side contact portion 53 and the rod side contact portion 23, the distance from the axial center of the screw changes along the circumferential direction. Due to this non-round shape, once the washer-side abutment portion 53 and the rod-side abutment portion 23 abut, relative rotation in the circumferential direction beyond this is restricted while the axial centers of the two are aligned. In particular, since the washer-side abutment portion 53 and the rod-side abutment portion 23 are not formed over the entire circumference of the linear motion rod 10 but are partially formed in the circumferential direction, the washer 50 and the linear motion These shaping processes of the rod 10 can be, for example, simple chamfering and pressing.

  As shown in FIG. 4, when the washer 50 is inserted into the linear motion rod 10 and the piston member 100 is further tightened, the linear motion rod 10 and the washer 50 are engaged circumferentially by the auxiliary relative rotation preventing mechanism B first. When the piston member 100 is further tightened, in the first relative rotation preventing mechanism A, the female screw side tapered surface of the seat portion 102 enters the recess of the washer side tapered surface of the washer 50, and the female screw side unevenness 104 and the first receiving portion The side asperities 64 engage and the state shown in FIG. 1 is obtained. As shown in FIG. 5A, when the piston member 100 tries to rotate in the fastening direction Y, the inclined surfaces 104Y and 64Y abut each other, as shown in FIG. 5A. Allow relative slide while narrowing the distance between the two in the axial direction. On the other hand, when the piston member 100 tries to rotate in the loosening direction X, the vertical surfaces (surfaces on the side with strong inclination) 104X and 64X abut each other to prevent relative movement between the two. In particular, in the first relative rotation preventing mechanism A, as the distance between the female screw side seat portion 102 and the first receiving portion 60 is reduced by tightening the piston member 100, engagement between the female screw side unevenness 104 and the first receiving portion side unevenness 64 As a result, the engagement strength on the loosening direction X side is increased. Here, the inclination angle of the female screw tapered surface and the inclination angle of the washer tapered surface are different from each other. In particular, the inclination angle of the washer tapered surface from the axial center is the inclination angle of the female screw tapered surface from the axial center By setting the width to be narrower than that, it is also possible to tighten without rattling regardless of the pitch of the saw teeth formed on the respective tapered surfaces.

  As described above, according to the seal structure of the first embodiment, since the outer seal fitting portion 210 is formed on the piston member 100, the piston ring 90 can be easily assembled. Along with this, since it is not necessary to consider elastic deformation of the piston ring 90, it is possible to select a material of high rigidity and high wear resistance. Further, since the piston ring 90 can be held in the axial direction by the washer 50 and the piston member 100, it is possible to prevent the piston ring 90 from falling off.

  Further, by interposing the washer 50, the first relative rotation preventing mechanism A is configured between the female screw side seat portion 102 of the piston member 100 and the first receiving portion 60 of the washer 50, while the insertion hole 52 of the washer 50 The auxiliary relative rotation prevention mechanism B is configured between the rod side cooperation area 17 of the linear movement rod 10. As a result, when the piston member 100 or the linear motion rod 10 tries to relatively rotate in the loosening direction, the circumferential engaging action of both the first relative rotation preventing mechanism A and the auxiliary relative rotation preventing mechanism B The relative rotation of the piston member 100 is restricted, and reverse rotation or loosening is prevented. Therefore, even if vibration or the like occurs, it is possible to obtain a fastening state that does not loosen at all. On the other hand, when the linear motion rod 10 and the piston member 100 rotate relative to each other in the tightening direction, the one-way clutch structure of the first relative rotation preventing mechanism A permits relative rotation of the washer 50 and the piston member 100. It is possible to do it freely.

  Further, since the piston member 100 is not loosened by the mechanical structure of the first relative rotation preventing mechanism A and the auxiliary relative rotation preventing mechanism B, it is not necessary to retighten the piston member 100 more than necessary. The piston ring 90 can be provided with an appropriate clamping force.

  In the first embodiment, as the first relative rotation preventing mechanism A, the case in which the female screw-side unevenness 104 and the first receiving portion-side unevenness 64 have a saw blade shape is illustrated, but the present invention is not limited to this. For example, as shown in FIG. 5 (B), it is also possible to make each other's unevenness into a mountain shape (both are inclined surfaces). In this case, when the piston member 100 rotates in the loosening direction X, the inclined surfaces 104X and 64X tend to move relative to each other, but along the inclined surface, the female screw side unevenness 104 and the first receiving portion side unevenness 64 will try to leave. If this moving distance (the separating angle α) is set larger than the lead angle of the piston member 100, even if the piston member 100 is loosened, the female screw side unevenness 104 and the first receiving portion side unevenness 64 are further separated I can not loosen it. In addition, although the unevenness of the cross-sectional isosceles triangle was illustrated in this FIG. 5B, as shown in FIG. 5C, it loosens more than the inclination angle of the inclined surfaces 104Y and 64Y contacted at the time of fastening rotation. It is also preferable to make the inclination angles of the inclined surfaces 104X, 64X in contact with each other gentle. In this way, the circumferential distance P between the inclined surfaces 104Y and 64Y, which must be overcome each other at the time of fastening rotation, can be shortened, so that rattling (gap) after fastening can be reduced.

  Moreover, as application of FIG. 5 (A)-(C), as shown in FIG.5 (D), the wavelike unevenness which curved the ridge and the valley is also preferable, and it can obtain smooth operativity at the time of fastening. it can. Furthermore, in the first embodiment, although the concavities and convexities extending in the radial direction are illustrated, it is also preferable to form a spiral (spiral) groove or peak (concave and convex) as shown in FIG. 6 (A). Further, as shown in FIG. 6 (B), even in the case of grooves or peaks (concave and convex) extending linearly, they can be arranged to be inclined such that the circumferential direction phase changes with respect to the radial direction of the screw. Further, as shown in FIG. 6C, it is also preferable to adopt a so-called embossed shape in which a plurality of fine asperities are formed in both the circumferential direction and the radial direction (planar shape) of the screw.

  Furthermore, as in the first embodiment, the concavo-convex shapes of the female screw-side concavo-convex 104 and the first receiving part-side concavo-convex 64 do not necessarily have to match (similarity). For example, different ones of the various shapes in FIGS. 5 and 6 can be selected and combined with each other.

  In the first embodiment, although the case where the female screw side tapered surface has a convex shape and the washer side tapered surface has a concave shape is illustrated, the present invention is not limited to this. For example, the female screw side tapered surface has a concave shape, a washer The side tapered surface can be convex. On the other hand, both of them can also be non-taper surfaces perpendicular to the screw axis. Further, for example, if the elastic deformation of the washer 50 is effectively used, it is not necessary to make the inclination angles of the two tapered surfaces coincide with each other. Of course, only one of the piston member 100 or the washer 50 may have a tapered surface. Furthermore, by making both of the tapered surfaces convex or concave, it is possible to make use of the elastic deformation of the washer to bring them into close contact. Moreover, in order to obtain the elasticity of the washer 50, it is preferable that the basic shape of the washer 50 be a so-called spring washer shape or a disc spring shape having a spiral shape.

  In addition, although the linear motion rod 10 of the first embodiment has a groove (constriction) in the middle of the end portion 12c, in detail, at the boundary between the rod-side cooperation region 35 and the male screw portion 13, It is not limited to this. A structure in which the rod-side cooperation region 35 and the male screw portion 13 are continuous without a groove is also preferable, and the strength of the linear motion rod 10 can be increased. Also, although the case where the stepped portion 20 is formed at the boundary between the main body portion 12a and the end portion 12c is shown, the present invention is not limited to this, and the main body portion 12a and the end portion 12c may be continuous with the same diameter. Good.

  Furthermore, as an application of the auxiliary relative rotation preventing mechanism B according to the first embodiment, as shown in FIG. 7A, as the rod side cooperation area 17 of the linear motion rod 10, a plurality of points around the end 12c (herein The rod side contact part 23A may be formed at two places. As shown in FIG. 7B, a projection 23B may be formed as a rod-side cooperation area 17 of the linear motion rod 10 so as to be convex outward in the radial direction from the periphery of the end 12c. As shown in FIG. 7C, as the rod side cooperation area 17 of the linear motion rod 10, the end 12c may be a polygon 23C (here, a hexagon) in cross section. Furthermore, as shown in FIG. 7 (D), the end 12c may be formed into an elliptical shape 23D in cross section as the rod side cooperation area 17 of the linear motion rod 10. Both have a “cross section non-circular shape” shape. At this time, although not particularly shown, it is preferable that the insertion holes 52 of the washer 50 also have similar shapes corresponding thereto, but under the condition that both can be engaged in the circumferential direction, it is necessary to make both similar shapes Absent.

  Further, in the case of this structure, as shown in FIG. 8A, the tapered surface 11 is formed on the linear motion rod 10, and the tapered surface 51 is formed on the washer 50 to be the inserted member. It is preferable to abut. As a result, if the tapered surfaces 11 and 51 are pressed against each other by tightening the washer 50 with the piston member 100, the axial centers of the washer 50 and the linear motion rod 10 can be aligned with high accuracy. The inner seal member 82 is interposed between the tapered surfaces 11 and 51 so that the tapered surface 11 abuts on the inner seal member 82 to suppress oil leakage.

  In this structure, the radial sizes of the cooperation member (washer) 50 and the piston member 100 are substantially the same, and the piston ring 90 is accommodated in the outer seal fitting portion 210 on the piston member 100 side and held by the washer 50. ing. Therefore, as shown in FIG. 8B, it is possible to form the outer seal fitting portion 210 on the washer 50 side, accommodate the piston ring 90 therein, and hold it by the piston 100. In this case, it is possible to define the washer 50 which is an inserted member as a piston and to define the piston 100 which is an inserted member as an internal thread for preventing the washer 50 from falling off. Hereinafter, in the second and subsequent embodiments as well, it will be described first that the cooperation member (washer) can also serve as the piston or the definitions of the washer and the piston can be reversed appropriately.

  Next, a seal structure according to a second embodiment will be described with reference to FIGS. 9 and 10. In addition, description is abbreviate | omitted about the structure or members which are the same as or similar to the first embodiment.

  As shown in FIG. 10A, in the linear motion rod 10, a rod side cooperation region 17 is formed so as to overlap with the male screw portion 13. When viewed from the axial direction, the rod-side cooperation area 17 is such that a partial arc of a sectioned circular shape formed along the apex of a thread is omitted (or cut) along the chord. It becomes a shape, and the part of this string becomes the rod side contact part 23. That is, a part of the thread is omitted so as to be continuous in the axial direction, so that an imaginary plane P orthogonal to the radial direction and directed radially outward is constituted, and this imaginary plane P is a rod side contact portion 23 It becomes. Therefore, the minimum radius 17Y of the rod side cooperation area 17 is set smaller than the maximum radius 13X of the male screw portion 13.

  Furthermore, in the present embodiment, the valley bottom 13 a of the screw thread remains around the rod-side contact 23 in the axial direction. As a result, the function of screwing with the piston member 100 remains. Specifically, in the rod-side contact portion 23, it is preferable to omit two thirds of the height of the screw thread as the upper limit, and more preferably, omit it as the upper limit one half of the screw thread height. Do. Therefore, the minimum radius (minimum distance) 17Y of the rod-side cooperation area 17 is larger than the minimum radius (valley radius) 13Y from the axial center of the male screw portion 13. In the present embodiment, the rod-side contact portion 23 is formed at three positions where the phase difference in the circumferential direction is 23 degrees.

  As shown in FIG. 10 (B), the insertion hole 52 through which the piston rod in the washer 50 can be inserted is a piston side cooperation area which is non-circular when viewed from the axial direction. The insertion hole 52 has a partial arc shape concentric with the axis of the screw, and has a shape in which the remaining portion is cut off like a chord into a straight line, so this chord is a washer side contact portion It will be 53. In the present embodiment, the washer-side abutting portions 53 are formed at three positions that have a phase difference of 120 degrees in the circumferential direction. The washer-side abutment portions 53 abut on the rod-side abutment portions 23 of the rod-side cooperation area 17 so as to engage with each other in the circumferential direction to configure the auxiliary relative rotation preventing mechanism B.

  Furthermore, in the present embodiment, the outer seal fitting portions 56 and 210 are formed in an opposing state on the outer peripheral surface of the washer 50 and the outer peripheral surface of the piston member 100, respectively. Thus, the piston ring 90 is housed in the pair of outer seal fittings 56,210.

  As described above, in the seal structure of the second embodiment, as shown in FIG. 9, between the insertion hole 52 of the washer 50 and the rod-side cooperation area 17 formed in an overlapping manner on the male screw 13 of the linear motion rod 10. The auxiliary relative rotation preventing mechanism B can be configured as follows. Therefore, since the engagement position with the washer 50 can be freely changed within the range where the rod side cooperation area 17 exists, the piston 10 and the piston ring 90 can be fixed simply by changing the axial dimension of the washer 50. You can adjust the position. A sleeve may be interposed between the washer 50 and the step 20 of the linear motion rod 10. In this case, the fixed value position of the piston 10 can be adjusted only by changing the axial dimension of the sleeve. Furthermore, in this case, since the valley bottom of the thread ridge is left as much as possible in the rod-side contact portion 23 of the rod-side cooperation region 17, the decrease in the fastening force with the piston member 100 hardly occurs There is.

  In addition, although the linear motion rod 10 of the 2nd embodiment illustrated the case where the rod side cooperation area 17 is not provided in the main-body part 12a, making the cross-sectional shape of the main body part 12a substantially correspond with the rod side cooperation area 17 It is also possible to extend this rod side cooperation field 17 to main part 12a by this. Of course, it is also possible to eliminate the main body 12a itself.

  FIG. 11 shows another modification of the second embodiment. As shown in FIG. 11A, in the rod-side cooperation region 17 formed to overlap with the male screw portion 13, the rod-side contact portion 23 in which the apex of the thread is omitted in a concave shape when viewed from the axial direction It is formed. More specifically, the rod-side contact portion 23 is configured such that the apexes of the threads are recessed in a V shape, and is formed at equal intervals in the circumferential direction at twelve places. The minimum distance (bottom of the recess) 17Y from the axial center of the rod-side contact portion 23 is set smaller than the maximum radius 13X of the male screw 13 and larger than the minimum radius (valley radius) 30bY of the male screw 13. Ru.

  Therefore, as shown in FIG. 11 (B), the insertion hole 52 of the washer 50 assembled to the linear motion rod 10 is also radially inwardly convex so that the insertion hole 52 of the washer 50 has a similar shape to the rod side cooperation region 17 The contact portions 53 are formed at equal intervals in the circumferential direction at twelve places. As a result, the washer 50 and the linear motion rod 10 can be engaged in the circumferential direction.

  In the second embodiment, in the rod-side cooperation area 17 formed in the male screw 13, the minimum distance 17Y from the axial center of the rod-side contact 23 is smaller than the minimum radius (valley radius) 30bY of the male screw 13. Although the case where it sets large is illustrated, the present invention is not limited to this. For example, as shown in FIG. 12A, in the male screw portion 13, an axial groove deeper than the valley bottom of the thread may be formed, and this may be used as the rod side contact portion 23. As a result, the minimum distance 17 </ b> Y from the axial center of the rod-side contact 23 is smaller than the minimum radius (valley radius) of the male screw 13. In this case, the thread of the male screw 13 is partially omitted including the valley bottom. In the insertion hole 52 of the washer 50, a washer side contact portion 53 which is convex inward in the radial direction is also formed, and the minimum distance from the axial center is determined by the minimum radius of the male screw 13 (valley radius, ie diameter of valley). Make it smaller. As a result, it is possible to increase the engagement dimension of the washer-side contact portion 53 and the rod-side contact portion 23 in the circumferential direction.

  Further, in the first and second embodiments, the case where the inclined surface (taper surface) is formed on the washer 50 and the piston member 100 to abut the both is illustrated, but the present invention is not limited to this. As shown in FIG. 12B, cylindrical surfaces are formed on both the washer 50 and the piston member 100, and the first receiving portion side unevenness 64 is formed on the cylindrical surface of the washer 50, and a female screw is formed on the cylindrical surface of the piston member 100. By forming the side asperities 104, they may be engaged with each other in the circumferential direction.

  Furthermore, although the case where the linear motion rod 10 has the step part 20 is illustrated in 1st and 2nd embodiment, this invention is not limited to this. For example, as shown in FIG. 13 as an application of the first embodiment, it is also possible to fasten the cooperation member (washer) 50 so as to sandwich the pair of piston members 100, 100 from both sides. Under the present circumstances, a pair of receiving part 60 used as the 1st relative rotation prevention mechanism A is formed in the both sides of cooperation member 50, and each receiving part 60, 60 is engaged with seat 102 of piston member 100. In this manner, the piston members 100 disposed on both sides are prevented from relative rotation in the loosening direction with respect to the linear motion rod 10 by the presence of the receiving portions 60 formed on the cooperation member 50. Ru.

  In this case, the outer seal fitting portions 210, 210 are formed in each of the pair of piston members 100, 100, and the outer seal fitting portions 56, 56 are also formed in both ends of the cooperation member (washer) 50. be able to. This makes it possible to hold the two piston rings 90, 90 at the boundary between the pair of piston members 100, 100 and the cooperation member (washer) 50.

  Further, as an application of the second embodiment, it is also possible to fasten the cooperative member (washer) 50 as shown in FIG. 14 so as to be sandwiched by the pair of piston members 100 from both sides. In the linear motion rod 10, the stepped portion 20 is omitted and the male screw portion 13 is formed there, and the rod side cooperation region 17 is formed so as to overlap with the male screw portion 13. A pair of receiving portions 60 to be the first relative rotation preventing mechanism A is formed on both sides of the cooperation member 50, and the receiving portions 60, 60 are engaged with the seat portion 102 of the piston member 100. In this manner, the piston members 100 disposed on both sides are prevented from relative rotation in the loosening direction with respect to the linear motion rod 10 by the presence of the receiving portions 60 formed on the cooperation member 50. Ru.

  Although the idea of FIGS. 13 and 14 realizes that the pair of piston members 100, 100 is fixed at any place on the linear motion rod, only one of the pair of piston members is substantially fixed. The other may be made to function as a female screw body. Moreover, it is also possible that the cooperation member 50 doubles as a part of piston. Specifically, as shown in FIG. 15, a piston member 100A which doubles as an internal thread is fastened from one side to an interlocking member (washer) 50 having receiving portions 60, 60 on both sides, and an internal thread from the other side. By fastening 100B, the three members of the piston member 100A, the linkage member 50, and the female screw 100B can be fixed at any place. Here, the outer seal fitting portion 210 is formed only on the side of the piston member 100A, and one piston ring 90 is disposed there.

  Furthermore, as in the structure of FIG. 16 which is a modification of the seal structure of the linear motion system of FIG. 15, in the washer 50, an arm which wraps around to the polygonal peripheral surface of the internal thread 100B or a plane opposite to the seat portion 102. It is also preferable to form the relative rotation preventing mechanism A by forming the arm 58 and engaging the arm 58 and the female screw 100B in the circumferential direction.

  Next, the seal structure of the third embodiment will be described with reference to FIGS. 17 and 18. The third embodiment is an application of the seal structure shown in FIG. 11 of the second embodiment, and the description of members identical or similar to these will be omitted. This seal structure is characterized in that the independent washer (linkage member) 50 can be omitted by integrally providing the function of the washer (linkage member) 50 to the piston member 100.

  As shown in FIG. 18, in the insertion hole 100a having a female screw portion 106a screwed with the male screw portion 13, the piston member 100 is formed with a piston side cooperation region 106b which is non-circular in cross section when viewed from the axial direction. The piston side cooperation area 106b is provided so as to axially protrude in a ring shape on the opposite side of the seat portion 102 of the piston member 100. However, it may be provided on the seat portion 102 side, and overlaps with the female screw portion 106a. It may be formed as follows.

  In the piston side cooperation area 106b, female screw side contact parts 108 convex inward in the radial direction are formed at equal intervals in the circumferential direction on the inner peripheral surface of the insertion hole 100a. As a result, the female screw side contact portion 108 can be engaged in the circumferential direction with the rod side contact portion 23 which is formed to be recessed in the male screw portion 13 of the linear motion rod 10. As described above, the female screw side contact portion 108 is axially thinly provided on the opposite side of the seat portion 102 of the piston member 100 so that it can be elastically deformed radially outward. By relatively rotating the linear motion rod 10 and the piston member 100 with a desired force, the piston side contact portion 108 is elastically deformed outward, and the circumferential engagement with the rod side contact portion 23 is released. Can.

  Therefore, as shown in FIG. 17, a positioning sleeve 18 (also defined as a member to be inserted) is disposed between the step portion 20 of the linear motion rod 10 and the piston member 100. On the other hand, if the piston member 100 is urged in a direction to tighten with a desired force, relative rotation can be permitted while the rod side contact portion 23 and the female screw contact portion 108 repeatedly repeat engagement and release. Can be fixed in the middle of the external thread. More preferably, by forming at least one of the rod-side contact portion 23 and the female screw-side contact portion 108 into a saw blade shape, rotation in the tightening direction is permitted, and rotation in the loosening direction is restricted. Let it work.

  Further, the insertion hole of the sleeve 18 is a basic hole 18A into which the linear motion rod 10 is inserted, and an annular inner seal housing having a diameter larger than the basic hole 18A and continuing to the end face of the linear motion rod 10 on the main body side. It has holes 18B. A step 18C is formed between the inner seal receiving hole 18B and the basic hole 18A. An annular inner seal member 82 is accommodated in the inner seal accommodation hole 18B, and axially engages with the step 18C. Therefore, by tightening the piston member 100, the inner seal member 82 is pressed against the step 21 of the linear motion rod 19 through the sleeve 18, and the working fluid is sealed. Here, a housing recess 18D is formed on the outer peripheral surface of the sleeve 18, and the auxiliary seal member 83 is housed therein, whereby the space between the piston member 100 and the sleeve 18 is sealed. The piston member 100 and the sleeve 18 may be integrally formed, in which case the auxiliary seal 83 can be omitted.

  In the first to third embodiments, the rod-side contact portion 23 of the rod-side cooperation region 17 is mainly illustrated as extending linearly in the axial direction, but the present invention is not limited to this. For example, as shown in FIGS. 19 (A) and 19 (B), it is also preferable to form the rod side contact portion 23 in a helically inclined manner with respect to the axial direction. At this time, it is desirable that the spiral direction of the rod side contact portion 23 be the same as the spiral direction of the thread of the male screw portion, and the lead thereof be set larger than the lead of the male screw portion. As a result, when the female screw body rotates in the loosening direction, when the cooperative member (for example, the washer) rotates with the female screw body (for example, the piston), the cooperative member is pressed against the female screw body due to the difference in the lead. The mechanism A can be engaged more firmly to prevent loosening.

  Further, in the first to third embodiments, in the outer seal fitting portion 210 formed on the circumferential surface of the piston member 100, the case where the piston ring 90 is brought into contact with the step portion 205 to position in the axial direction is illustrated. However, the present invention is not limited to this. For example, as shown in FIG. 20, the inner peripheral surface of the piston ring 90 may be tapered surfaces 90a and 90b to enhance the sealing performance. In this case, the outer seal fitting portions 210 and 56 are formed on the outer peripheral surface of the piston member 100 and / or the washer 50, and tapered surfaces 203 opposed to the tapers 90a and 90b of the piston ring 90 on the respective peripheral surfaces. It is sufficient to form 55a. The tapered surface 203 has a large diameter on the side of the seal portion 105 a and a small diameter on the side of the end surface 101. That is, it inclines so that it may become small diameter gradually toward the washer 50 side. The tapered surface 55 a is inclined toward the piston member 100 so as to gradually decrease in diameter. In this case, the tapered surfaces 90a and 90b of the piston ring 90 and the tapered surfaces 203 and 55a of the piston member 100 and / or the washer 50 are brought into close contact and in the axial direction by using the holding force of the piston member 100 and the washer 50. It can be positioned.

  Furthermore, in the modification shown in FIG. 8 of the first embodiment, the case where the inner seal member 82 is interposed between the tapered surface 11 of the shaft portion 12 of the linear motion rod 10 and the tapered surface 51 of the piston 50 is illustrated. However, the present invention is not limited to this. For example, as shown in FIG. 21, it is also possible to install an inner seal member 82 on the main body 12a of the linear motion rod 10, and to make the outer periphery of the inner seal member 82 a tapered surface 11. The inner seal member 82 is axially positioned by coming into contact with the step 21.

  The insertion hole 50a of the cooperation member 50 has a basic hole 50a2 and an annular inner seal receiving hole 250 continuous from the middle of the insertion hole 50a to the end face. A tapered surface 51 is formed on the inner periphery of the inner seal accommodation hole 250, and the tapered surface 51 and the tapered surface 11 of the inner seal member 82 are in close contact with each other, thereby simultaneously positioning the cooperation member 50 in the axial direction. , Suppress oil leaks. At this time, if the fastening force of the piston member 100 is adjusted, the degree of close contact between the two tapered surfaces 11 and 51 can be changed appropriately.

  In the first to third embodiments, the piston side tapered surface is formed in the seat portion 102 of the piston member 100, and the structure in which the self-excitation centering is performed with the washer 50 is illustrated. It is not limited to. For example, as in the modification of the third embodiment shown in FIG. 22A, in the insertion hole 100a of the piston member 10, the first insertion hole (inner seal receiving hole) 100a1 having a large diameter and the second small diameter The insertion hole (basic hole) 100a2 may be coaxially provided, and the inner seal member 82 may be accommodated in the first insertion hole (inner seal accommodation hole) 100a1. An annular tapered surface 82a is formed on the inner peripheral surface of the inner seal member 82, and the annular tapered surface 82a and the tapered surface 11 of the linear motion rod 10 are brought into contact with each other to make linear motion with the piston member 100. Direct centering between the rods 10 is also preferred.

  Furthermore, here, on the outer peripheral surface 105 of the piston member 10, an annular outer seal fitting portion 210 continuous from the middle to the end surface 101 is formed, and the piston ring 90 is inserted therein. A ring-shaped outer seal holding member 270 is fixed to the end surface 101 of the piston member 10 by an axially extending bolt 272. By bringing the outer seal holding member 270 into contact with the piston ring 90, the piston ring 90 is prevented from falling off the outer seal fitting portion 210.

  Furthermore, in the first to third embodiments, the cooperative member (washer) 50 is configured as a separate member from the linear motion rod 10, and the structure that prevents the loosening of the piston member 100 using the cooperative member 50 is illustrated. However, the present invention is not limited to this. For example, as in the modification of the first embodiment shown in FIG. 22 (B), in the linear motion rod 10, a function equivalent to that of the cooperation member (washer) 50 may be integrally provided. That is, the linear motion rod 10 integrally has the expanded portion 50X, and the first receiving portion 60 facing the seat portion 102 of the piston member 100 may be formed in the expanded portion 50X. As a result, a first relative rotation preventing mechanism A is configured between the expanded portion 50X of the linear motion rod 10 and the piston member 100. When the first relative rotation preventing mechanism A tries to rotate in a direction in which at least the piston member 100 is loosened with respect to the linear movement rod 10 in which it is screwed, the first receiving portion 60 and the seat portion 102 engage with each other Prevent relative rotation.

  At this time, the insertion hole 100a of the piston member 100 is formed with a first insertion hole (inner seal receiving hole) 100a1 having a large diameter and a second insertion hole (basic hole) 100a2 having a small diameter. The inner seal member 82 is accommodated in the first insertion hole (inner seal accommodation hole) 100a1, and the actuating fluid can be sealed by bringing the inner seal member 82 into contact with the end face on the linear movement rod 10 side. .

  In addition, although the case where the washer side contact part of a cooperation member (washer) becomes concave in the circumferential direction inside is illustrated mainly in the said embodiment, you may become convex in the circumferential direction inside.

  FIG. 23 (a) is a plan view of the seal structure 1 according to the fourth embodiment, and FIG. 23 (b) is a front view of the seal structure 1. FIG. FIG. 24 is a cross-sectional view taken along the line AA of FIG. As shown in these figures, the seal structure 1 seals the working fluid while fastening the piston member 100 to the linear motion rod 10 and fixing them to each other, and is formed on the linear motion rod 10 and the piston member 100 And a relative rotation prevention mechanism 40. As shown in FIG. The piston member 100 and the fixing male screw body 30 are “inserted members” into which the direct acting rod 10 is inserted, and the piston body 300 is configured by these.

  As shown in FIG. 24, the linear motion rod 10 has, from the center toward the end, a substantially rod-like (substantially cylindrical) main body portion 12 a having a large diameter and a cylindrical positioning portion having a smaller diameter than the main body portion 12 a A cylindrical end 12 c having a diameter smaller than that of the positioning portion 12 b is configured. Therefore, the first axial step 11a is formed at the boundary between the main body 12a and the positioning end 12b, and the second axial step 11b is formed at the boundary between the positioning end 12b and the end 12c. An external thread 13 in which an external thread spiral groove is formed is provided on the outer peripheral surface of the end 12c, and in this embodiment, the external thread 13 has a first external thread spiral groove 14 which is a right thread, and a left thread. Two types of externally threaded spiral grooves of the second externally threaded spiral groove 15 are formed to overlap on the same area.

  FIG. 25 shows the male screw portion 13 of the linear motion rod 10 in an enlarged manner. In the male screw portion 13, a substantially crescent-shaped screw thread 13a continuous in a plane direction perpendicular to the axial center (screw shaft) C is one side (left side of the figure) and the other side (right side of figure) of the male screw portion 13. By alternately forming the screw thread 13a in this manner, two types of spiral grooves, that is, a spiral groove pivoting clockwise and a spiral groove pivoting counterclockwise, are formed between the screw threads 13a. You can do it.

  In this embodiment, by doing this, two types of external thread spiral grooves of the first external thread spiral groove 14 and the second external thread spiral groove 15 are formed in the external thread portion 13. Therefore, the male screw portion 13 can be screwed with any female screw body of the right screw and the left screw. In addition, for details of the male screw portion 13 in which two types of male screw spiral grooves are formed, refer to Japanese Patent No. 4663813 according to the inventor of the present application.

  Referring back to FIG. 24, the piston member 100 is a cylindrical member, and has an annular outer peripheral surface 105 opposed to the inner peripheral surface of the tube 4, a pair of end surfaces 101 opposed in the axial direction, and coaxial with the outer peripheral surface. The insertion hole 100a is formed in the shape of a circle. The outer circumferential surface 105 is close to the inner circumferential surface of the tube 4 to form a seal portion 105 a that restricts the movement of the working fluid. At least one (in this case, both) of the end face 101 serves as a pressure receiving face 101a that receives the pressure of the working fluid. The linear motion rod 10 is inserted into the insertion hole 100a.

  The insertion hole 100a has a first insertion hole (inner seal receiving hole) 100a1 having a large diameter and a second insertion hole (basic hole) 100a2 having a small diameter coaxially in detail. The first insertion hole 100a1 is located on the center side of the linear motion rod 10, and has a size slightly larger than the diameter of the main body 12a or the positioning portion 12b of the linear motion rod 10. The second insertion hole 100a2 is located on the axial end side of the linear motion rod 10, and a first female screw portion 106a is formed on the inner peripheral surface. As a result, the hole side stepped portion 100b is formed at the boundary between the first insertion hole 100a1 and the second insertion hole 100a2.

  A cylindrical inner seal member 82 is disposed on the inner periphery of the first insertion hole (inner seal receiving hole) 100 a 1 and the outer periphery of the positioning portion 12 b of the linear motion rod 10. The axial size of the inner seal member 82 is slightly longer than the axial dimension of the positioning portion 12 b of the linear motion rod 10. As a result, both ends of the inner seal member 82 engage with the hole side stepped portion 100 b and the first shaft side stepped portion 11 a. The outer diameter of the inner seal member 82 is substantially the same as the inner diameter of the first insertion hole 100a1.

  As described above, when the end of the linear motion rod 10 is inserted into the first insertion hole 100a1 of the piston member 100, the outer peripheral surface of the inner seal member 82 is in close contact with the inner peripheral surface of the first insertion hole 100a1 of the piston member 100. Further, both end surfaces of the inner seal member 82 abut on the hole side step portion 100b and the first shaft side step portion 11a. That is, the linear motion rod 10 and the piston member 100 are positioned in the axial direction. Although the inner seal member 82 is set to be made of synthetic resin, it is not necessarily required to be made of synthetic resin, and it is not particularly limited as long as it can maintain airtightness.

  On the outer peripheral surface 105 of the piston member 100, an annular outer seal fitting portion 210 which is continuous from the middle to the end surface 101 on the fixing female screw body 30 side is formed. The outer seal fitting portion 210 constitutes a small diameter surface 201 which continues to the end surface 101 on the side of the fixing female screw body 30 on the circumferential surface, and the piston ring 90 is inserted therein, abutted and fitted thereto. Ru. The small diameter surface 201 is smaller in diameter than the outer peripheral surface (seal portion 105 a) of the piston member 100, and the piston ring 90 is positioned in the axial direction by the seal portion 105 a and the step 205 formed on the small diameter surface 201. The axial dimension of the piston ring 90 is set to be slightly larger than the axial dimension of the small diameter surface 201, and the piston ring 90 minutely protrudes from the piston member 100 toward the female screw 30 for fixing. The fixing female screw body 30 is set to have a diameter larger than the small diameter surface 201. Accordingly, when the fixing female screw body 30 and the piston member 100 are fastened, the end face of the fixing female screw body 30 abuts on the piston ring 90, and the piston ring 90 is fixed. That is, the piston ring 90 is sandwiched between the piston member 100 and the female screw body 30 for fixation. Thereby, the internal female screw body 30 for fixation is disposed in the vicinity of the end face of the piston member 100 and functions as an outer seal holding member for pressing the piston ring 90 toward the outer seal fitting portion 210 side. Of course, the material of the piston ring 90 is not limited to the synthetic resin, and is not particularly limited as long as the sealing property can be maintained.

  The first female screw portion 106 a of the piston member 100 is screwed into the male screw portion 13 of the linear motion rod 10. Accordingly, the piston member 100 is internally screwed to the linear motion rod 10. Further, the fixing female screw body 30 is screwed into the male screw portion 13 from the outside of the piston member 100. Therefore, the piston member 100 is fixed by being sandwiched between the inner seal member 82 and the female screw body 30 for fixing.

  The first female screw portion 106 a of the piston member 100 is formed with a first female screw spiral groove which is a right-handed screw. That is, the first female screw portion 106 a is screwed with the first male screw spiral groove 14 in the male screw portion 13 of the linear motion rod 10.

  The external shape and the like of the fixing female screw body 30 are not particularly limited, but in the present embodiment, they are substantially matched with the piston member 100. Accordingly, the outer peripheral surface 31 of the fixing female screw body 30 is a cylindrical surface. Furthermore, the piston member 100 is provided with a screw hole 32 penetrating in the axial direction. In the second female screw portion 33 which is the inner peripheral surface of the screw hole 32, a second female screw spiral groove which is a left screw is formed. That is, the fixing female screw body 30 is screwed with the second male screw spiral groove 15 in the male screw portion 13 of the linear motion rod 10. On the end face 38, a relative rotation preventing mechanism 40 described later is disposed.

  FIGS. 26 (a) to 26 (d) are diagrams showing the relative screwing operation of the piston member 100 and the female screw body for fixing 30 in a state in which the relative rotation preventing mechanism is ignored. Since the piston member 100 and the female screw body for fixing 30 are in the relation of reverse screw mutually, as shown in the figures (a) and (b), both rotate relative to the linear motion rod 10 in the same direction. When it is made to rotate (or when both are fixed and the linear motion rod 10 is rotated), it will move to the mutually opposite direction along the axial center C.

  Specifically, as shown in FIG. 6A, the rotational direction of the piston member 100 and the fixing female screw 30 with respect to the linear movement rod 10 is counterclockwise as viewed from the fixing female screw 30 (upper side in the drawing). In such a case, the piston member 100 and the female fixing screw 30 move in the direction approaching each other along the axial center C direction. However, when the piston member 100 and the fixing female screw body 30 are in close contact with each other, the simultaneous rotation of the piston member 100 and the female fixing screw body 30 is naturally restricted since the piston member 100 and the female screw body 30 for fixing can not approach any further.

  When the rotational direction of the piston member 100 and the fixing female screw body 30 is clockwise as viewed from the fixing female screw body 30 side (upper side in the drawing) as shown in FIG. The screw 100 and the fixing female screw 30 move in the direction away from each other along the axial center C direction. However, when the piston member 100 is already in contact with the inner seal member 82 (see FIG. 24), the piston member 100 can not move any further, so simultaneous rotation of the piston member 100 and the female screw body 30 for fixation is possible. Is naturally regulated.

  Of course, as shown in FIG. 7C, when only the fixing female screw 30 is rotated clockwise, the fixing female screw 30 can be loosened. As a result, the piston ring 90 can be disengaged from the outer seal fitting portion 210. Further, as shown in FIG. 6D, when only the fixing female screw body 30 is rotated clockwise, and at the same time the piston member 100 is rotated counterclockwise, both are simultaneously loosened.

  As can be understood from the above screwing operation, when the piston member 100 and the fixing female screw body 30 are sufficiently tightened on the linear motion rod 10, the piston member 100 and the fixing female screw body 30 rotate in the same direction. Is structurally impossible (see FIGS. 26 (a) and (b)). In other words, the linear motion rod 10 has a structure in which it can not be rotated relative to the piston member 100 and the female fixing screw 30. On the other hand, it can be understood that when only the fixing female screw body 30 is rotated or when the piston member 100 and the fixing female screw body 30 are rotated in opposite directions, the fastening state is loosened. That is, in this fastening structure, by restricting the “relative rotation after fastening” of the piston member 100 and the female screw body 30 for fixing, the piston member 100 and the female screw body 30 for fixing can maintain the state of not being structurally detached. As a result, the piston ring 90 does not come off permanently.

  Below, the relative rotation prevention structure 40 employ | adopted by this embodiment is demonstrated below.

  Referring back to FIG. 24, the relative rotation prevention mechanism 40 is engaged with the first engagement hole 191 serving as a female screw hole formed in the piston member 100 and the second engagement hole 181 formed in the female screw body 30 for fixation. A male screw 110 for common use and an annular washer 150 are provided. The second engagement hole 181 is an insertion hole, and the first engagement hole 191 formed in the piston member 100 is a non-insertion hole. An engagement female thread portion is formed on the inner peripheral surface of the first engagement hole 191. The male screw 110 for engagement is screwed with the first engagement hole 191 via the second engagement hole 181. As a result, the male screw body for engagement 110 is consistently inserted into the first engagement hole 191 and the second engagement hole 181, and the relative rotation of the piston member 100 and the female screw body for fixation 30 is restricted. The female screw hole may be formed on the second engagement hole 181 side instead of the first engagement hole 191 side.

  As shown in FIG. 27, the male screw 110 for engagement is a so-called bolt and has a head 120 and a shaft 130. A screw body side seat 122 is formed at a portion corresponding to the lower part or the root of the head 120. The shaft portion 130 is formed with a cylindrical portion 130 a and a screw portion 130 b. Of course, the cylindrical portion 130a is not essential.

  The first receiving portion 160 is formed on one side (upper surface side in FIG. 27) of the washer 150. The first receiving portion 160 faces the screw body side seat portion 122, and a first engagement mechanism A is formed between the two. In the first engagement mechanism A, the first receiving portion 160 and the screw side seat 122 engage with each other when at least the screw side seat 122 tries to rotate in a direction in which the engagement male screw 110 is loosened. Thus, relative rotation between the first receiving portion 160 and the screw body side seat portion 122 with respect to the rotational direction is prevented.

  The second receiving portion 170 is formed on the other side of the washer 150 (the lower surface side in FIG. 27). The second receiving portion 170 faces the fixing female screw body 30.

  A member side seat portion 182 facing the second receiving portion 170 of the washer 150 is formed in the fixing female screw body 30. A second engagement mechanism B is configured between the member-side seat portion 182 of the internal female screw 30 for fixation and the second receiving portion 170 of the washer 150. When the second engagement mechanism B tries to rotate at least the washer 150 in the loosening direction together with the male screw 110 for engagement, the second receiving portion 170 and the member side seat portion 182 engage with each other, and the rotational direction Relative rotation between the second receiving portion 170 and the member-side seat portion 182 is prevented.

  When the engagement male screw body 110 tries to rotate in the loosening direction by the action of the first engagement mechanism A and the second engagement mechanism B, the engagement male screw body 110 and the fixing female screw body 30 Relative rotation is regulated. As a result, the engagement male screw body 110 is prevented from loosening.

  As shown in FIG. 28, as the first engagement mechanism A, a screw body side unevenness 124 is formed on the screw body side seat portion 122 of the engagement male screw body 110. The screw body side unevenness 124 has a saw blade shape provided continuously in the circumferential direction. The direction in which each of the screw-body-side irregularities 124 extends, that is, the direction in which the ridge line extends, is the radial direction of the male screw 110 for engagement. As a result, the screw body side unevenness 124 radially extends from the axial center.

  Further, the screw body side seat portion 122 is formed with a radially inclined screw body side tapered surface 126. The screw body side tapered surface 126 is inclined so that the center side approaches the screw tip, and as a result, it has a conical shape convex on the screw tip side. More preferably, the screw-body-side unevenness 124 described above is formed on the screw-body-side tapered surface 126.

  As shown in FIG. 29, as the first engagement mechanism A, the first receiving portion 160 of the washer 150 is formed with the first receiving portion side unevenness 164 that engages with the screw body side unevenness 124. The first receiving portion side unevenness 164 has a saw blade shape provided continuously in the circumferential direction. The direction in which each of the first receiving-side unevenness 164 extends, that is, the direction in which the ridge line extends, is along the radial direction of the male screw 110 for engagement. As a result, the first receiving portion side unevenness 164 radially extends from the center of the through hole 152 of the washer 150.

  Furthermore, preferably, the first receiving portion 160 is formed with a radially inclined washer side tapered surface 166. The washer-side tapered surface 166 has a conical shape inclined so that the center side approaches the screw tip, and as a result, it has a conical shape concave on the screw tip side. The first receiving portion side unevenness 164 described above is formed on the washer side tapered surface 166.

  As a result, when tightening the male screw body for engagement 110, in the first engagement mechanism A, the screw body side tapered surface 126 of the screw body side seat portion 122 enters into the recess of the washer side tapered surface 166 of the washer 150. The unevenness 124 engages with the first receiving section unevenness 164. As shown in FIG. 30 (A), when the male screw for engagement 110 tries to rotate in the fastening direction Y, the inclined surfaces 124Y and 164Y abut each other, and the distance between the two is set in the axial direction. Allow relative slide, while releasing. On the other hand, when the male screw bodies for engagement 110 try to rotate in the loosening direction X, the vertical surfaces (surfaces on the side with strong inclination) 124X and 164X abut each other to prevent relative movement between the two. In particular, the first engagement mechanism A engages with the screw body side unevenness 124 and the first receiving portion side unevenness 164 as the distance between the screw body side seat portion 122 and the first receiving portion 160 is reduced by tightening the engaging male screw body 110. And the engagement strength on the loosening direction X side is increased. Here, the inclination angle of the screw body side tapered surface 126 and the inclination angle of the washer side tapered surface 166 are made different from each other. In particular, the inclination angle from the axial center of the washer side tapered surface 166 is the axial center of the screw body side tapered surface 126 By setting the angle of inclination smaller than the angle of inclination, it is possible to tighten without rattling regardless of the pitch of the sawtooth formed on each tapered surface.

  Referring back to FIG. 29, the outer wall 172 of the second receiving portion 170 of the washer 150 varies in the distance from the axial center of the screw along the circumferential direction. Specifically, the outer wall 172 has a circular shape that is eccentric to the axial center of the screw (the center of the insertion hole 152).

  On the other hand, the member-side seat portion 182 of the female screw body 30 for fixing includes a fitting portion 184 for accommodating the second receiving portion 170 of the washer 150, and the inner wall of the fitting portion 184 is also a screw. It has a circular shape eccentric to the axis. The amount of eccentricity is the same in the second receiving portion 170 and the fitting portion 184, and the diameter difference (margin clearance) of the second receiving portion 170 and the fitting portion 184 is set smaller than the amount of eccentricity.

  Therefore, as shown in FIG. 27, when the second receiving portion 170 of the washer 150 is accommodated in the fitting portion 184 of the fixing female screw body 30, the both fit together, and the axial centers of the screws are aligned. As it is, relative rotation between the two in the circumferential direction is restricted. That is, the second receiving portion 170 and the fitting portion 184 act as a second engagement mechanism B.

  As a result of the above, according to the relative rotation preventing mechanism 40, by interposing the washer 150, the first engagement mechanism A is configured between the screw body side seat portion 122 and the first receiving portion 160, and the member side seat portion A second engagement mechanism B is formed between 182 and the second receiving portion 170, and when the engagement male screw body 110 is loosened, the restricting action of both the first engagement mechanism A and the second engagement mechanism B The engagement male screw body 110 circumferentially engages with the fixing female screw body 30, thereby preventing reverse rotation, that is, loosening. Therefore, even if vibration or the like occurs, it is possible to obtain a fastening state that does not loosen at all. As a result, the engagement male screw body 110 can reliably regulate the relative rotation of the piston member 100 and the fixing female screw body 30.

  Furthermore, here, as the first engagement mechanism A, the screw body side unevenness 124 and the first receiving portion side unevenness 164 have a plurality of saw blade shapes that are continuous in the circumferential direction, and act as a so-called ratchet mechanism or one-way clutch mechanism. . As a result, in the fastening operation, relative movement of the screw body side unevenness 124 and the first receiving portion side unevenness 164 is allowed to realize smooth relative rotation, while in the loosening operation, the screw body side unevenness 124 and the first receiving portion The relative movement of the side unevenness 164 is completely restricted. As a result, the workability at the time of fastening and the subsequent prevention of loosening can be rationally compatible.

  Further, as the first engaging mechanism A, since the screw body side tapered surface 126 and the washer side tapered surface 166 are formed on the screw body side seat portion 122 and the first receiving portion 160, the contact area between the two is increased. It can. Further, the fastening force in the axial direction of the engagement male screw body 110 also acts in the radial direction by the tapered surface. By pressing the tapered surfaces in the radial direction, centering can be performed in a self-excitation manner. As a result, the concentricity of the male screw 110 for engagement and the washer 150 can be enhanced, and the engagement accuracy of the screw-side unevenness 124 and the first receiving-portion unevenness 164 can be enhanced. It is also preferable to slightly increase the inclination of the screw-side tapered surface 126 on the convex side and reduce the inclination angle of the recessed washer-side tapered surface 166 to a minute difference between the angles. In this case, the tapered surfaces can be brought into contact with each other little by little from the center toward the radially outer side as the tightening pressure increases.

  Further, in the second engagement mechanism B, it is avoided that the shapes of the outer wall of the second receiving portion 170 of the washer 150 and the inner wall of the fitting portion 184 of the fixing female screw body 30 become concentric with the axis of the screw. doing. In other words, in the inner wall of the fitting portion 184 and the outer wall of the second receiving portion 170, the distance from the axial center of the screw changes along the circumferential direction. With this shape, when the inner wall of the fitting portion 184 and the second receiving portion 170 are fitted, relative rotation in the circumferential direction is restricted while the axial centers of the fitting portions 184 are aligned. In particular, here, since it has an eccentric right circular shape, it is possible to prevent relative rotation between the both while making shape processing of the washer 150 and the female screw body for fixing 130 extremely easy.

  In addition, although the case where the screw-body side unevenness | corrugation 124 and the 1st receiving part side unevenness | corrugation 164 were sawtooth shape was illustrated as a 1st engagement mechanism A here, this invention is not limited to this. For example, as shown in FIG. 30 (B), it is also possible to make each other's unevenness into a mountain shape (both are inclined surfaces). In this way, when the engagement male screw body 110 rotates in the loosening direction X, the inclined surfaces 124X and 164X try to move relative to each other, but along the inclined surface, the screw body side unevenness 124 and the first receiving portion The side unevenness 164 tries to separate. If this movement distance (the angle of separation α) is set larger than the lead angle of the male screw 110 for engagement, even if the male screw 110 for engagement is loosened, the screw side unevenness 124 and the first receiving portion unevenness 164 are further increased. Because it tries to separate, it can not be loosened. Although FIG. 30B exemplifies the concavities and convexities having an isosceles triangle in cross section, as shown in FIG. It is also preferable to make the inclination angles of the inclined surfaces 124X and 164X in contact gentle. In this manner, the circumferential distance P between the inclined surfaces 124Y and 164Y, which must be overcome each other at the time of fastening rotation, can be shortened, so that rattling (gap) after fastening can be reduced.

  Moreover, as an application of FIG. 30 (A)-(C), as shown to FIG. 30 (D), the wave-shaped unevenness | corrugation which curved the ridge and the valley is also preferable. Smooth operability can be obtained at the time of fastening. Furthermore, although the unevenness | corrugation extended to radial direction was illustrated here, as shown to FIG. 31 (A), it is also preferable to form the groove | channel or peak (concave and convex) of spiral shape (spiral shape). Further, as shown in FIG. 31 (B), even in the case of grooves or ridges (concave and convex) extending linearly, they can be arranged to be inclined so that the circumferential phase changes with respect to the radial direction of the screw. Further, as shown in FIG. 31C, it is also preferable to adopt a so-called embossed shape in which a plurality of fine asperities are formed in both the circumferential direction and the radial direction (planar shape) of the screw.

  Furthermore, as in the relative rotation prevention mechanism 40, the concavo-convex shapes of the screw-body-side concavo-convex 124 and the first receiving-part-side concavo-convex 164 do not necessarily have to match (similar). For example, different ones of the various shapes in FIGS. 30 and 31 can be selected and combined with each other.

  As an application of the relative rotation preventing mechanism 40, as shown in FIG. 32A, the outer wall of the second receiving portion 170 of the washer 150 and the inner wall of the fitting portion 184 of the member side pedestal portion 182 have axial centers of screws. Alternatively, the partial arc shape S may be concentric with the other, and the remaining portion may be cut off linearly like a chord G. That is, also in this case, in the inner wall of the fitting portion 184 and the outer wall of the second receiving portion 170, the distance from the axial center of the screw varies along the circumferential direction. Therefore, the inner wall of the fitting portion 184 and the second receiving portion 170 are engaged by the shape of the chord G, and relative rotation in the circumferential direction is restricted.

  Further, as shown in FIG. 32B, the outer wall of the second receiving portion 170 of the washer 150 has a partial arc shape S concentric with the axial center of the screw, and the remaining portion forms a radially extending projection T You can do it. At this time, a recess K which is recessed in the radial direction is formed on the inner wall of the fitting portion 184. By the engagement of the protrusion T and the recess K, the inner wall of the fitting portion 184 and the second receiving portion 170 are engaged, and relative rotation in the circumferential direction is restricted. Under the present circumstances, it is preferable to make the hollow K formed in the fitting part 184 into small circular shape (partial circular arc). This is because when the fitting portion 184 is cut, the depression K can be formed by only one processing by the rotary blade. Although not shown in the drawings, a recess (notch) may be formed on the second receiving portion 170 side of the washer 150, and a protrusion may be formed on the fitting portion 184 side so as to protrude radially inward.

  According to the seal structure 1 of the fourth embodiment, both the inner seal member 82 and the piston ring (outer seal member) 90 can be inserted from the end faces of the internal female screw body 30 and the piston member 100. Further, the inner seal member 82 can be held by the fixing female screw body 30 and the linear movement rod 10, and the piston ring 90 can be held by the fixing female screw body 30 and the piston member 100. As a result, the assembly operation is extremely easy.

  Further, according to the seal structure 1, the piston member 100 itself has the first female screw portion 106 a and is screwed with the first male screw spiral groove 14 of the linear motion rod 10, so the force received from the outside is The piston member 100 can transmit to the linear motion rod 10 by itself. The minimum diameter (valley diameter) of the first male screw spiral groove 14 is increased as compared with the conventional structure in which the axially slidable piston member is fixed to the linear motion rod 10 so as to be sandwiched by the female screw body. As a result, the durability of the linear motion rod 10 can be enhanced.

  Further, the male screw portion 13 of the linear motion rod 10 has a first male screw spiral groove 14 and a second male screw spiral groove 15, and the piston member is fixed by the fixing female screw body 30 screwed into the second male screw spiral groove 15. Since the rotation in the loosening direction 100 is restricted, the piston member 100 does not loosen even if a repeated external force or vibration acts on the piston member 100. As a result, the inner seal member 82 and the piston ring (outer seal member) 90 do not separate. Moreover, unlike the conventional locking, it does not rely on the frictional force between the flank surface of the thread of the male screw and the flank of the thread of the female screw, but the fixing female screw 30 and the piston member 100 Since the structural interference is prevented from being loosened by the operation interference, it is not necessary to retighten the fixing female screw body 30 more than necessary, and the fatigue of the linear motion rod 10 can be reduced simultaneously with the facilitation of the fastening operation. Further, the deterioration of the inner seal member 82 and the piston ring (outer seal member) 90 held by the fastening force of the fixing female screw 30 is also reduced.

  Similarly, as long as the relative rotation prevention mechanism 40 is not detached or broken, even if plastic deformation or wear occurs in the piston member 100, the piston member 100 may be detached from the linear movement rod 10 It will be surely prevented and security can be enhanced.

  Further, since the first male screw spiral groove 14 in which the piston member 100 is screwed and the second male screw spiral groove 15 in which the fixing female screw body 30 is screwed have the same minimum diameter (valley diameter), the piston member If the fixing female screw 30 is brought into close contact with the screw 100, the external force acting on the piston member 100 is dispersed by the piston 100 and the fixing female screw 30, and the first male screw spiral groove 14 and the second male screw spiral groove 15 are dispersed. It can be transmitted. This also makes it possible to improve the durability of the linear motion rod 10.

  Furthermore, in the present embodiment, the relative rotation preventing mechanism 40 completely prevents relative rotation of the piston member 100 and the fixing female screw body 30, so that only the fixing female screw body 30 is rotated, and the linear motion rod 10 alone. It prevents you from getting out of it. In particular, in the relative rotation preventing mechanism 40, the male screw 110 for engagement engaged with the piston member 100 and the female screw 30 for fixing itself is also prevented from rotating in the loosening direction, so the male screw 110 for engagement is disengaged. There is no need to worry. As a result, even if vibration or the like occurs, the function of the relative rotation preventing mechanism 40 is maintained, so that it is possible to prevent the piston member 100 from falling off the linear motion rod 10.

  In addition, when the piston member 100 needs to be removed at the time of maintenance of the inner seal member 82 and the piston ring (outer seal member) 90, the first engagement mechanism A between the washer 150 and the male screw 110 for engagement, Or, the engagement of any of the second engagement mechanism B between the washer 150 and the female fixing screw 30 is broken, the male screw 110 for engaging is removed, and then the female screw 30 for fixing is removed and then fixed. Loosen the female screw body 30. Thus, the piston member 100, the linear motion rod 10, and the female screw body 30 for fixation can be reused by limiting the destruction target at the time of maintenance to the washer 150 and the male screw body 110 for engagement. That is, according to the present embodiment, maintenance of the piston member 100, the female screw body 30 for fixing, and the linear movement rod 10 is simplified while completely preventing displacement and falling off of the linear movement rod 10 relative to the linear movement rod 10 after assembly. It can be done at low cost. When the material of the washer 150 or the male screw 110 for engagement is selected to be softer than the material of the piston member 100 or the female screw 30 for fixing, the washer 150 can be forcibly removed when the male screw 110 for engagement is forcibly removed. Or it is also possible to make the engagement male screw body 110 break preferentially.

  Next, with reference to FIG. 33, a seal structure according to a fifth embodiment of the present invention will be described. In addition, since it is the same as that of 4th embodiment except the relative rotation prevention mechanism, it limits to a relative rotation prevention mechanism here, and demonstrates. In this relative rotation preventing mechanism, although the male screw body for engagement 110 is the same as that of the fourth embodiment, the structure of the washer 150 and the female screw body for fixing 130 is partially different. The description of the male screw 110 for common use is omitted.

  The washer 150 is thinner as compared with the fourth embodiment as shown in FIG. 34A, and is also convex in the direction of the screw tip on the side of the second receiving portion 170 facing the female screw body 30 for fixing. A second washer-side tapered surface 176 is formed.

  In the same manner as in the fourth embodiment, the outer wall 172 of the second receiving portion 170 of the washer 150 and the inner wall of the fitting portion 184 have an eccentric right circular shape, so that they fit in each other. Rotation is regulated.

  Referring back to FIG. 33, on the bottom surface of the fitting portion 184 of the fixing female screw body 130, a member-side tapered surface 186 which is concave toward the screw tip side is formed. As a result, by being in contact with the second washer-side tapered surface 176 of the washer 150, the fastening force of the male screw 110 is received via the washer 150.

  Further, a pulling space 188 is formed in part of the inner wall of the fitting portion 184. The pulling space 188 is secured by expanding the inner wall of the fitting portion 184 radially outward and increasing the depth of the recess. A gap is formed in a part of the outer wall of the second receiving portion 170 of the washer 150 by the pulling space 188.

  When the fixing female screw body 30 is fixed using the male screw body for engagement 110 and the washer 150, as the first engagement mechanism A, the screw body side unevenness 124 of the male screw body for engagement 110 and the first receiving portion side of the washer 150 side The unevenness 164 engages. Furthermore, as the second engagement mechanism B, the outer wall of the second receiving portion 170 of the washer 150 and the inner wall of the fitting portion 184 are engaged with each other, whereby rotation in the circumferential direction is restricted. As a result, the reverse rotation of the engagement male screw body 110 is prevented, that is, it does not loosen.

  FIG. 34B illustrates an operation in the case of forcibly loosening the male screw body for engagement 110 at the time of maintenance of the inner seal member 82 and the piston ring (outer seal member) 90. For example, by inserting the end of the minus driver D into the pulling space 188, the end is inserted to the back side of the washer 150. In this state, by lifting the tip of the minus driver D, the second receiving portion 170 of the washer 150 can be deformed upward. As a result, the second engagement mechanism B by the second receiving portion 170 and the fitting portion 184 is released. In this state, if the male screw body for engagement 110 is rotated in the loosening direction, the washer 150 can also be rotated together, so the male screw body for engagement 110 can be loosened.

  In the fifth embodiment, although the case where the pull-up space 188 is formed in the fitting portion 184 of the fixing female screw body 30 is illustrated, the present invention is not limited to this. For example, as shown in FIG. 35A, by forming the inclined surface 177A on the outer wall of the washer 150, the tip of the minus driver D can be inserted into the back side of the washer 150 (the female screw body 30 for fixing). Make it Further, as shown in FIG. 35 (B), an insertion concave portion 177B is formed on the periphery of the washer 150 so as to be separated from the fixing female screw body 30. The tip of the minus driver D can be inserted into the back side of the washer 50 through the insertion recess 177B. In addition, a crescent-shaped gap is created by utilizing the difference between the outer diameter of the washer 150 and the inner diameter of the fitting portion 184, and the crescent-shaped gap (not shown) is used to create a flathead screwdriver D. It is preferable that the tip be insertable on the back side of the washer 150. Of course, such a gap is not limited to a crescent shape.

  Next, with reference to FIG. 36, a seal structure according to a sixth embodiment of the present invention will be described. In addition, since it is the same as that of 4th embodiment except the relative rotation prevention mechanism, it limits to a relative rotation prevention mechanism here, and demonstrates. As shown in FIG. 36 (B), the screw body side seat portion 122 of the male screw body for engagement 110 has a planar shape, and a saw blade shaped screw body side unevenness 124 is formed there. In addition, a neck 132 for holding the washer 150 is formed at the root of the shaft portion 130 of the engagement male screw body 110.

  As shown in FIG. 36A, the first receiving portion 160 of the washer 150 also has a planar shape, and a saw-tooth shaped first receiving portion side unevenness 164 is formed there. In the insertion hole 152 of the washer 150, an engagement protrusion 152A that protrudes to the inner peripheral side is formed, and engages with the constriction 132 of the male screw 110 for engagement. As a result, it becomes possible to integrate (engage) the male screw 110 for engagement and the washer 150 in advance.

  Further, on the second receiving portion 170 of the washer 150, a washer side step portion 174 extending in the axial direction of the screw is formed. Here, the washer side step part 174 is comprised by the nail | claw bent to the female screw body 30 side for fixation.

  On the other hand, the fixing female screw body 30 has a flat portion 31 a as a member side stepped portion 182 A of the member side seat portion 182. The flat portion 31 a is formed by cutting out a part of the cylindrical outer peripheral surface 31. The member side step portion 182A has a level difference which falls to the screw tip side. The distances from the axial centers of the screws of the washer side step 174 and the member side step 182A coincide with each other. Therefore, as shown in FIG. 36C, when the male screw body for engagement 110 is tightened, the washer side step portion 174 and the member side step portion 182A are engaged, and the relative rotation of the washer 150 and the female screw body 30 for fixing It is prevented.

  In the sixth embodiment, although the case where both are integrated in advance by the constriction 132 of the male screw body for engagement 110 and the engagement protrusion 152A of the washer 150 is illustrated, the method is not limited to this. For example, by providing magnetism on at least one side, the male screw body for engagement 110 and the washer 150 can be integrated by magnetic force. In addition, the male screw 110 for engagement and the washer 150 can be integrated in advance by adhesive, (spot) welding, press-fitting (frictional force). Moreover, it is also possible to integrate the male screw body for engagement 110 and the washer 150 by using an auxiliary tool such as an O-ring.

  In the sixth embodiment, the flat portion 31a formed on the outer peripheral surface 31 of the fixing female screw 30 is engaged with the washer 150 to prevent relative rotation between the two, but the present invention is limited thereto I will not. For example, as in the application example shown in FIG. 37A, the shaft engaging portion 175 can be formed on the washer 150, and this shaft engaging portion 175 can be engaged with the male screw 13 of the linear motion rod 10. The shaft engaging portion 175 has a ring shape surrounding the male screw portion 13. By inserting the male screw portion 13 into the shaft engaging portion 175, the washer 150 is engaged with the male screw portion 13. As a result, relative rotation of the washer 150 and the female screw body 30 for fixation is prevented. The shape of the shaft engaging portion 175 is not limited to the ring shape, and may be engaged with the male screw portion 13 such as a partial arc shape shown in FIG. 37B or a V shape for sandwiching the male screw portion 13 You can choose any shape you can. Further, as shown in FIG. 37C, two or more bolt insertion holes are provided for one washer 150, and rotation around the other bolt axis is prevented by two or more engaging male screw bodies 110. Configuration is also possible.

  Furthermore, although the case where the washer side step part 174 is formed in the outer periphery of the washer 150 was illustrated in 6th embodiment, this invention is not limited to this. For example, as shown in FIG. 37D, the washer side step (projection) 174 can be formed on the inner side of the outer edge of the washer 150. In the fitting portion 184 of the fixing female screw body 30, a member-side stepped portion (dent) 182A for accommodating the washer-side stepped portion 174 is formed. As a result, the washer side step (projection) 174 and the member side step (recess) 182A are engaged to prevent relative rotation.

  Next, a seal structure according to a seventh embodiment of the present invention will be described with reference to FIG. In addition, since it is the same as that of 4th embodiment except the relative rotation prevention mechanism, it limits to a relative rotation prevention mechanism here, and demonstrates. As shown in FIG. 38A, the outer shape of the washer 150 is a circle eccentric to the axial center of the screw. The washer 150 is a so-called disc spring, and elastically deforms in the axial direction when receiving the fastening force from the engagement male screw body 110.

  As shown in FIG. 38 (B), the washer 150 is accommodated in an eccentric circular fitting portion 184 formed on the fixing female screw 30. The screw body side seat portion 122 of the male screw body 110 for engagement is formed with the screw body side unevenness 124 on the center side, and engages with the first receiving portion side unevenness 164 of the washer 150. Further, on the outer side of the screw body side unevenness 124 in the screw body side seat portion 122, a pressing surface 123 which is in direct contact with the fixing female screw body 30 is formed.

  Furthermore, the gap L between the bottom surface of the fitting portion 184 and the screw-body-side unevenness 124 of the male screw 110 for engagement is set somewhat smaller than the axial dimension of the washer 150. As a result, when the male screw 110 for engagement is tightened, the washer 150 is sandwiched between the bottom surface of the fitting portion 184 and the screw-side unevenness 124 to be elastically deformed. However, the amount of elastic deformation is sufficient to suppress relative rotation between the screw-body-side unevenness 124 and the first receiving portion-side unevenness 164. This is because the fastening force of the engagement male screw body 110 is directly transmitted to the fixing female screw body 130 via the pressing surface 123. According to the present embodiment, the strength and rigidity of the washer 150 itself can be lowered, so that the manufacturing cost can be reduced.

  In the fourth to seventh embodiments, the head portion 120 of the male screw 110 for engagement protrudes from the female screw 30 for fixation, but the depth of the fitting portion 184 of the female screw 30 for fixation is made deeper If so, even the head 120 can be accommodated in the fitting portion 184.

  In the fourth to seventh embodiments, the outer shape of the washer 150 is illustrated as being circular or a partial arc, but other shapes may be adopted. For example, the outer shape of the washer 150 may be oval, oval, polygonal or the like. That is, in order to prevent relative rotation by fitting with the fitting portion, it is sufficient if the outer shape of the washer 150 with respect to the axial center is "non-perfectly circular (not concentric perfect circle)". Further, in the seventh embodiment, the case where the washer 150 is elastically deformed as a disc spring is illustrated, but it may be elastically deformed like a spring washer. Furthermore, it is also preferable to form a washer by a composite material in which a metal and an elastically deformable material (for example, rubber etc.) are integrated, and to make it elastically deformable.

  Furthermore, in the fourth to seventh embodiments, the washer 150 is installed on the fixing female screw body 30, and the first receiving portion side unevenness 164 is formed on the washer 150b to engage with the screw body side unevenness 124 of the engagement male screw body 110. Although the structure to be combined is illustrated, the present invention is not limited thereto. For example, as shown in FIG. 39, it is possible to directly form the first receiving portion side unevenness 164 on the flat surface of the fixing female screw body 30 and omit the washer 150. If the material strength of the fixing male screw body 30 is made stronger than the engaging male screw body 110, the first receiving portion of the fixing female screw body 30 can be obtained even if the engaging male screw body 110 is forcibly loosened at the time of maintenance or the like. The side irregularities 164 need not be damaged.

  Next, with reference to FIG. 40, a seal structure according to an eighth embodiment of the present invention will be described. In addition, since it is the same as that of 4th embodiment except the relative rotation prevention mechanism, it limits to a relative rotation prevention mechanism here, and demonstrates.

  As shown in FIG. 40A, the relative rotation preventing mechanism 40 includes a first engagement hole 191 which is an internal thread hole formed in the piston member 100 and a second engagement hole formed in the internal thread 30 for fixation. It comprises 181, an engagement pin 111 as an engagement member, a spring 113 as biasing means, and a male screw body 115 for release. The second engagement hole 181 is an insertion hole, and includes a large diameter hole 181A formed on the piston member 100 side and a small diameter hole 181B formed on the shaft end side and smaller than the large diameter hole 181A. A release female screw portion 181C for screwing with the release male screw body 115 is formed on the inner peripheral surface of the small diameter hole 181B.

  The first engagement hole 191 formed in the piston member 100 is a non-insertion hole, which has the same diameter as the large diameter hole 181A and is set to be longer than the large diameter hole 181A. The engagement pin 111 is a rod member having a diameter that substantially matches the inner diameter of the first engagement hole 191 and the large diameter hole 181A, and is longer than the large diameter hole 181A and shorter than the first engagement hole 191. The spring 113 is accommodated on the back side (bottom side) of the first engagement hole 191, and biases the engagement pin 111 accommodated in the first engagement hole 191 toward the fixing female screw body 30. .

  Therefore, when the axial centers of the first engagement hole 191 and the large diameter hole 181A do not match, the engagement pin 111 is completely accommodated in the first engagement hole 191 against the force of the spring 113. Be done. On the other hand, when the axial centers of the first engagement hole 191 and the large diameter hole 181A coincide with each other, the biasing force of the spring 113 causes a part of the engagement pin 111 to enter the large diameter hole 181A and stop. As a result, the engagement pin 111 is simultaneously inserted into the first engagement hole 191 and the second engagement hole 181 (large diameter hole 181A), and the relative rotation of the piston member 100 and the female screw body 30 for fixation is restricted. Ru.

  When releasing the restriction by the engagement pin 111 at the time of maintenance or the like, the release male screw body 115 is inserted into the small diameter hole 181B and screwed with the release female screw portion 181C. The length of the shaft portion of the release male screw body 115 is substantially the same as the axial length of the fixing female screw body 30. Therefore, as shown in FIG. 40 (B), engagement is achieved by the tip of the release male screw body 115. The mating pin 111 can be pushed into the first engagement hole 191 side, and the regulation of the relative rotation by the engagement pin 111 can be released. Therefore, by screwing the release male screw body 115 into the small diameter hole 181B, the fixing female screw body 30 can be easily loosened.

  In the fourth to eighth embodiments, the structure in which the piston member 100 is disposed on the center side of the linear motion rod 10 and the female screw body 30 for fixing is disposed on the end side of the linear motion rod 10 has been described. Is not limited to this. For example, as shown in FIG. 41, the piston member 100 may be disposed on the end side of the direct acting rod 10, and the fixing female screw body 30 may be disposed on the central side of the direct acting rod 10. In this case, a first insertion hole (inner seal receiving hole) 35a1 having a large diameter and a second insertion hole (basic hole) 35a2 having a small diameter are coaxially provided inside the fixing female screw body 30, The second female screw portion 33 is formed on the inner peripheral surface of the insertion hole 35a2. As a result, by bringing the stepped portion at the boundary between the first insertion hole 35a1 and the second insertion hole 35a2 into contact with the end face of the inner seal member 82, the working fluid can be sealed and the male screw body 30 can be axially positioned. It becomes. The relative rotation preventing portion 40 may be performed by inserting the male screw 110 for engagement from the side of the female fixing screw 30 toward the piston member 100, but on the contrary, for fixing from the piston 100 The male screw 110 for engagement may be inserted toward the female screw 30.

  Furthermore, in the fourth to eighth embodiments, the case where the first male screw spiral groove 14 and the second male screw spiral groove 15 are formed so as to overlap over the entire axial direction of the male screw portion 13 of the linear motion rod 10 is illustrated. However, the present invention is not limited to this. As shown in FIG. 42, for example, when the piston member 100 is disposed on the center side of the linear motion rod 10 and the fixing female screw body 30 is disposed on the end side, the first male screw spiral groove 14 screwed with the piston member 100 is male screw. The second male screw spiral groove 15 screwed to the female screw body 30 for fixing, which is required throughout the axial direction of the portion 13, starts from the axial end of the male screw portion 13, and the region where the female screw body 30 for screwing is screwed It may be formed to the vicinity. That is, the male screw portion 13 of the present invention includes the case where the first male screw spiral groove 14 and the second male screw spiral groove 15 are formed in a partially overlapping manner in a limited area.

  Furthermore, in the fourth to eighth embodiments, the case where the lead directions of the first male screw spiral groove 14 and the second male screw spiral groove 15 are different (right screw, left screw) is illustrated, but the present invention It is not limited. For example, as shown in an enlarged view in FIG. 43, even if the first male screw spiral groove 14 and the second male screw spiral groove 15 have the same screw direction (lead direction) but have different leads (lead angles). Good. In this case, as shown in the same figure, by further forming a helical groove in the helical thread 13a constituted by the first male screw helical groove 14, the lead is L1 (lead angle θ1). The groove 14 and the second male screw spiral groove 15 in which the lead has L2 (lead angle is θ2) can be formed with the screw directions aligned.

  Furthermore, the male screw portion 13 of the linear motion rod 10 may not have the first male screw spiral groove 14 and the second male screw spiral groove 15 overlapping with each other. For example, as in the male screw portion 13 shown in FIG. 44, the first male screw spiral groove 14 has a large diameter and the second male screw spiral groove 15 has a small diameter, so that the large diameter side first male screw spiral groove 14 is on the center side, It is also possible to arrange the second male screw spiral groove 15 so as not to overlap the end side. In this case, when the piston member 10 is screwed into the first male screw spiral groove 14, the second male screw spiral groove 15 does not interfere in the diameter direction, and the fixing female screw body 30 is screwed into the second male screw spiral groove 15. In this case, the first external thread spiral groove 14 may not interfere in the axial direction.

  Next, with reference to FIG. 45, a seal structure according to a ninth embodiment of the present invention will be described. In addition, since a relative rotation prevention mechanism is the same as that of 4th embodiment, it limits and demonstrates to a different part from 4th embodiment, abbreviate | omitting description of a relative rotation prevention mechanism here.

  In this embodiment, the inner seal member 82 formed of a chemical material such as a thermoplastic resin or a thermosetting resin with respect to the first shaft side stepped portion 11 a of the linear motion rod 10 is a metal expansion ring 11. The inner seal member 82 itself also serves as a stopper for positioning the piston member 100 in the axial direction. Although the inner seal member 82 may be directly engaged with the first shaft side stepped portion 11a, in this case, it is necessary to increase the step of the first shaft side stepped portion 11a. Therefore, as in the present embodiment, the difference in level of the first shaft side step portion 11a directly formed on the linear motion rod 10 is made small, and the metal expansion ring 11 is engaged there, substantially. Increase the level difference.

  On the other hand, the first insertion hole 100 a 1 of the piston member 100 becomes an inner seal receiving hole 250 for receiving the inner seal member 82. The inner seal member 82 is formed with a tapered surface 82a which is tapered toward the shaft end on the outer peripheral surface, and the inner peripheral surface of the inner seal receiving hole 250 of the piston member 100 is a tapered surface opposed thereto. Therefore, by screwing the piston member 100 to the linear motion rod 10, as a result of the inner seal member 82 and the inner seal accommodation hole 250 pressing each other, high sealing performance can be secured. In addition, although the case where the piston member 100 side was made into a taper surface was illustrated here, you may make it form a taper surface in the linear motion rod 10 side.

  Furthermore, in the present embodiment, on the outer peripheral surface of the piston member 100, an annular outer seal fitting portion 210 which is continuous from the middle to the end surface on the fixing female screw body 30 side is formed. On the circumferential surface of the outer seal fitting portion 210, a small diameter surface 201 which is continuous to the end face on the side of the fixing male screw body 30 is formed. The small diameter surface 201 has a smaller diameter than the outer circumferential surface, and the piston ring 90 is installed there. The axial dimension of the piston ring 90 is set to be slightly larger than the axial dimension of the small diameter surface 201, and protrudes from the piston member 100 to the female screw body 30 for fixation. The fixing female screw 30 is set to have a diameter larger than that of the small diameter surface 201, and the outer diameter is circular. Therefore, when the fixing female screw body 30 is tightened to the piston member 100 side, the end face of the fixing female screw body 30 abuts on the piston ring 90, and the piston ring 90 is fixed. That is, the piston ring 90 is held between the piston member 100 and the female screw body 30 for fixing.

  As a result of the above, the inner seal member 82 and the piston ring 90 can be easily assembled as compared with the conventional case where the seal material is fitted while being elastically deformed. Along with that, since it is not necessary to consider elastic deformation of the inner seal member 82 and the piston ring 90, it is possible to select a material of high rigidity and high wear resistance. Although the case where the inner seal member 82 has a tapered structure is illustrated here, as in the application shown in FIG. 46, the inner peripheral surface of the piston ring 90 is made to be tapered surfaces 90a and 90b to enhance the sealing performance. You can also. In this case, the outer seal fitting portions 210 and 39 are formed on the outer peripheral surface of the piston member 100 and / or the female screw body 30 for fixation, and the inner peripheral surface of the piston ring 90 is tapered on each peripheral surface. And tapered surfaces 203 and 39a facing each other may be formed. Intimate contact between the tapered surfaces 90a and 90b of the piston ring 90 and the tapered surfaces 203 and 39a of the piston member 100 and / or the female internal thread 30 for fixation using the clamping force between the piston 100 and the female internal thread 30 for fixation it can.

  In the fourth to ninth embodiments, the relative rotation preventing mechanism 40 exemplifies the case where the engagement male screw body 110 is inserted from the fixing female screw body 30 side toward the piston member 100, but the present invention is not limited thereto. It may be inserted from the side of the piston member 100 toward the side of the male screw 110 for engagement. Moreover, although the case where the relative rotation prevention mechanism 40 is arrange | positioned one place in the circumferential direction was illustrated in 4th thru | or 9th embodiment, you may be arrange | positioned in multiple places of the circumferential direction.

  Furthermore, in the above embodiment, although the example of applying the piston connection structure to a hydraulic cylinder has been introduced, the present invention is not limited to this, and the pressure of fluid appropriate for the piston such as hydraulic cylinder, air cylinder, various dampers, etc. It is applicable to any linear motion system which obtains desired motion by applying or receiving pressure.

  Further, the embodiments of the present invention are not limited to the above embodiment, and it goes without saying that various modifications can be made without departing from the scope of the present invention. For example, the piston member of the present invention is provided with small holes penetrating to the front and back to make an orifice, and the input from the outside to the linear motion rod is damped by the small hole flow of the viscous fluid housed inside the tube. It can also be made to act on.

DESCRIPTION OF SYMBOLS 1 seal structure 10 direct acting rod 12 shaft part 12a main body part 12c end part 13 male screw part 14 first male screw spiral groove 15 second male screw spiral groove 17 rod side cooperation area 20 step 22 rod side seat 23 rod side contact part 23X male screw side contact area 23Y male screw side contact area 30 fixing female screw body 31 outer peripheral surface 31a of fixing female screw body flat portion 33 of female screw body for fixing second female screw portion 40 relative rotation preventing mechanism 50 cooperation member (washer, piston )
52 insertion hole 53 washer side contact part 53X first washer side contact area 53Y second washer side contact area 60 first receiving part 64 first receiving part side unevenness 70 second receiving part 82 inner seal member 90 piston ring ( Outer seal member)
Reference Signs List 100 piston member 100a insertion hole 102 seat portion 104 screw body side unevenness 105a seal portion 106a (first) female screw portion 106b piston side cooperation region 108 female screw side contact portion 110 engagement male screw body 111 engagement pin 115 release male screw body 150 washer 181 second engagement hole 191 first engagement hole 201 small diameter surface 203 tapered surface 210 outer seal fitting portion 250 inner seal receiving hole 300 piston body C shaft center (screw shaft)

Claims (19)

A piston body which is movably accommodated in the axial direction in a tube, holding the piston body, and the fluid to be applied to linear motion system and a linear motion rod you conjunction with reciprocation of the piston member Seal structure,
In the insertion hole into which at least a portion of the piston body is inserted, and in which the linear motion rod is inserted, and the outer peripheral surface facing the inner peripheral surface of the tube, the fluid is moved close to the inner peripheral surface. A piston member having a restricting seal portion;
An annular outer seal fitting portion formed on the outer peripheral surface of the piston member and having a diameter smaller than that of the seal portion and continuing to any one of a pair of end surfaces opposed in the axial direction;
An annular outer seal member that is in contact with the outer seal fitting portion of the piston member;
An outer seal holding member disposed in the vicinity of an end face of the piston member and axially pressing the outer seal member toward the outer seal fitting portion;
Equipped with
The end face of the piston member includes a tapered surface configured in a tapered manner,
The end face of the outer seal retaining member is tapered and includes a tapered surface capable of surface contact with the tapered surface of the piston member,
A relative rotation preventing mechanism is formed between the piston member and the outer seal holding member, in which the tapered surfaces of the piston member and the outer seal holding member abut against each other to prevent relative rotation between the piston member and the outer seal holding member. A seal structure of a direct acting system, characterized in that a holding member is fixed to an end face of the piston member . The relative rotation preventing mechanism includes a plurality of piston-side irregularities provided continuously in the circumferential direction on the tapered surface of the piston member and a plurality of reception-side irregularities provided in the circumferential direction on the tapered surface of the outer seal holding member. The seal structure of the linear motion system according to claim 1, wherein the seal structure is engaged with each other. The outer seal holding member is
It has a female member for holding member screwed to the male screw of the linear motion rod.
The seal structure of the linear motion system according to claim 1. The male screw portion of the linear motion rod is formed with a first male screw spiral groove and a second male screw spiral groove having different lead angles and / or lead directions,
Wherein the basic holes of the piston member, piston female screw portion to be screwed with the first male screw spiral groove of the linear rod is formed,
Hold unit for the internal thread portion of the outer seal holding member may be screwed with the second male screw spiral groove,
The seal structure of the linear motion system according to claim 3. The peripheral surface of the outer seal fitting portion is formed in a tapered shape in which the seal portion side has a large diameter and the end surface side has a small diameter.
The seal structure of the linear motion system according to any one of claims 1 to 4. The pressing surface of the outer seal holding member for pressing the outer seal member is formed in an annular tapered shape whose diameter gradually decreases toward the outer seal fitting portion .
The seal structure of the linear motion system according to any one of claims 1 to 5. The linear motion rod and an annular inner seal member disposed between the piston member or the outer seal holding member;
The piston member or the outer seal holding member is
A basic hole into which the linear motion rod is inserted;
One of a pair of axially opposed end surfaces of the piston member having a diameter larger than the basic hole and constituting at least a part of the piston body and having an insertion hole into which the linear motion rod is inserted With a continuous annular inner seal receiving hole up to
The inner seal member is in contact with the inner seal receiving hole.
The seal structure of the linear motion system according to any one of claims 1 to 6.   The seal structure of a linear motion system according to claim 7, wherein a step portion or a tapered surface axially engaged with the inner seal member is formed on an outer peripheral surface of the linear motion rod.   The seal structure of the linear motion system according to claim 7 or 8, wherein the peripheral surface of the inner seal accommodation hole has a tapered structure in which the diameter on the basic hole side is small and the diameter on the end face side is large. The linear motion rod has a rod-side cooperation region, which is non-circular in cross section when viewed from the axial direction, in a shaft portion having a male screw portion,
The piston member has, in the insertion hole, a female screw portion screwed with the male screw portion, and a piston side cooperation region which is not circular in cross section when viewed from the axial direction,
The rod-side cooperation region and the piston-side cooperation region are configured to be engaged with each other in the circumferential direction while permitting relative rotation due to an external force.
The seal structure of the linear motion system according to any one of claims 1 to 9. It comprises a cooperation member that constitutes at least a part of the piston body and has an insertion hole into which the linear movement rod is inserted,
The linear motion rod has a rod-side cooperation region, which is non-circular in cross section when viewed from the axial direction, in a shaft portion having a male screw portion,
The piston-side cooperation area that circumferentially engages with the rod-side cooperation area is formed in the one of the insertion holes of the piston member and the cooperation member by forming the inner circumference as a non-circular shape,
In the other of the insertion holes of the piston member and the cooperation member, a piston female screw portion to be screwed with the male screw portion of the direct acting rod is formed,
Between the said piston member and the said cooperation member, the relative rotation prevention mechanism which both engage in the circumferential direction is arrange | positioned, characterized by the above-mentioned.
The seal structure of the linear motion system according to any one of claims 1 to 3. The cooperative member also functions as the outer seal holding member.
The seal structure according to claim 11. In the basic hole into which the linear motion rod of the piston member is inserted , an internal thread portion to be screwed with the external thread portion of the linear motion rod is formed.
The seal structure of the linear motion system according to any one of claims 1 to 3. A piston member which is axially movably accommodated in a tube, is fixed to the linear movement rod in the tube, and receives a fluid pressure and transmits it to the linear movement rod,
A pressure receiving surface formed on at least one of a pair of axially opposed end surfaces for receiving the pressure of the fluid;
An insertion hole into which the linear motion rod is inserted;
A seal portion which is formed on an outer peripheral surface facing the inner peripheral surface of the tube and which restricts the movement of the fluid in proximity to the inner peripheral surface;
And an annular outer seal fitting portion formed on the outer circumferential surface, having a smaller diameter than the seal portion, and being continuous to the end face,
An annular outer seal member is locatable at the outer seal fitting portion,
The piston member according to claim 1, wherein the end surface includes a tapered surface circumferentially engaged with a tapered surface of a separate outer seal holding member for axially pressing the outer seal member. The tapered surface has a plurality of piston side irregularities provided continuously in the circumferential direction,
The piston member according to claim 14, wherein the piston side unevenness engages with a receiving side unevenness formed on a tapered surface of the outer seal holding member. The piston member according to claim 14 or 15 , wherein a circumferential surface of the outer seal fitting portion has a tapered structure in which the seal portion side has a large diameter and the end face side has a small diameter. The insertion hole is
A basic hole into which the linear motion rod is inserted;
An annular inner seal receiving hole having a diameter larger than the basic hole and continuing to the end face;
The piston member according to any one of claims 14 to 16, wherein an annular inner seal member is configured to be arrangeable in the inner seal receiving hole. The piston member according to claim 17 , wherein the circumferential surface of the inner seal receiving hole has a tapered structure in which the diameter on the side of the basic hole is small and the diameter on the end face is large. The piston member according to any one of claims 14 to 18 , wherein the insertion hole is formed with a female screw portion screwed with a male screw portion of the linear motion rod.